GEOGRAPHY SA II- CLASS VIII- ALL CHAPTERS IMPORTANT Questions
COMPREHENSIVE NOTES
CLASS-VIII
SUBJECT-GEOGRAPHY
CHAPTER-4 AGRICULTURE
TERM - 2
-COMPREHENSIVE NOTES
CLASS-VIII
SUBJECT-GEOGRAPHY
CHAPTER-4 AGRICULTURE
TERM - 2
-

 
 

 




-
 -



 
 









 



!
 


 
 



" #


$

 
 




 

 



%

 

! & '
  &



 




( $


 
 






$
!
! &
'
 !


 









" )


&
 


" $
 
 




 



  ! !

&
!



 

'
( *


 
 
 
#

 &
  +
  ,

( -
 
-


  '



 

 
 

&
.


 
 



'


+
-
 

,
/
 

&
!





0 1
 


 

0 $
 


 


-
2 &
 

 
 

 



 


 
  $
 
 


 
 
 

 

 
 
 
  &
 
$
 
 



 
 



 
 

 




-
 -



 
 









 



!
 


 
 



" #


$

 
 




 

 



%

 

! & '
  &



 




( $


 
 






$
!
! &
'
 !


 









" )


&
 


" $
 
 




 



  ! !

&
!



 

'
( *


 
 
 
#

 &
  +
  ,

( -
 
-


  '



 

 
 

&
.


 
 



'


+
-
 

,
/
 

&
!





0 1
 


 

0 $
 


 


-
2 &
 

 
 

 



 


 
  $
 
 


 
 
 

 

 
 
 
  &
 
$
 
 



 
 

CLASS VII PHYSICAL AND CHEMICAL CHANGE - SAII- SCIENCE

PHYSICAL AND CHEMICAL CHANGEVery  Short type questions                          

Questions:What is the chemical name of Baking Soda?

(Ans)  Sodium hydrogen carbonate (NaHCO₃).

Questions: What is Rust?

(Ans)  When iron oxide is hydrated, it is known as Rust(Fe₂O₃. XH₂O)

Questions: What type of change is photosynthesis?

(Ans)  Photosynthesis is a chemical change.

Questions: What do you understand by physical properties of a substance?

(Ans)  Properties like size, shape, colour and state of a substance are known as physical properties.

Questions: What is a chemical change?

(Ans)  A change in which a new substance with different properties is formed, is known as a chemical 
change.

Questions: What is malleability?

(Ans)  Malleability is a property by virtue of which a metal can be beaten into thin sheets without breaking.

Questions: Name four characteristics which are included in the physical properties of matter.

(Ans)  Properties such as shape, size, colour and state of a substance are called its physical properties.

Questions: Write the chemical formula of blue vitriol.

(Ans)   Crystals of copper sulphate pent hydrate (CuSO₄.5H₂O) are blue in colour. So, it is commonly 
known as blue vitriol.

Questions: Explain why rusting of iron objects is faster in coastal areas than in deserts.

(Ans)  In coastal areas, there is more moisture in air due to the presence of sea. In deserts, there is shortage 
of water and hence, air is almost dry. For rusting, both air (Oxygen) and moisture are essential. So, rusting is 
faster in coastal areas than in deserts.

Questions: What are the two important conditions for rusting? 

(Ans)  Presence of both water and oxygen are required to form rust on iron. 

Questions: What is freezing of water?

(Ans)  Freezing is the process in which water turns to ice when cold enough (below 0 °C temperature).

Questions: What is freezing point of water?

(Ans)  The freezing point is 0 °C at which water freezes.

Questions: What do you understand by melting?

(Ans)  The process of turning a solid to a liquid.

Questions: How melting and freezing related?

(Ans)  Melting (converts solid into liquid) is opposite to freezing (converts liquid into solid).

Questions: What is evaporation?

(Ans)  It is the process by which water molecules continuously change to vapor.

Questions:At what temperature water evaporates and what do we call it?

(Ans)  Evaporation of water occurs when water is heated to a temperature of 100 °C, which is called as 
boiling point of water.

 Questions:What is symbol?

(Ans) The symbol of an element is a short way of representing an element.

Questions: What Does A Symbol Represent?  

(Ans) A symbol represents one atom of an element.   Example: H stands for one atom of hydrogen

Short type questions                              

Questions: What is rusting? How can we prevent rusting?

(Ans)   When a piece of iron is left in open for some time, it acquires a film of brownish substance called rust.  The process is known as rusting.

We can prevent rusting by following methods:

(1) By painting or greasing: - Apply a coat of paint or grease regularly on iron articles.

(2) By galvanizing:-Deposit a layer of zinc or chromium on iron. The process is known as galvanization.

Questions:  Why setting of curd is regarded as a chemical change 

(Ans)  Curd is formed by adding some sour substance to milk and keeping it undisturbed for some hours. Some useful bacteria help in the setting of curd. Curd cannot be converted into milk. It is a different substance than milk. Hence, formation of curd is a chemical change.

Questions: What happens when magnesium oxide is dissolved in water?

(Ans)  When magnesium oxide is dissolved in water, magnesium hydroxide is formed.     

Mg O +H₂O ---------> Mg(OH)₂

Questions: What happens when baking soda is treated with vinegar?

(Ans)  Ethanoic acid reacts with sodium hydrogen carbonate to evolve brisk effervescence of carbon dioxide.

CH₃COOH + NaHCO₃        ------------> CH3COONa + CO₂ + H₂O 

Questions:  Is the burning of candle a physical change?

(Ans)  When a candle burns, both physical and chemical changes take place.

On burning candle, the wax melts but can be solidified again on cooling. This shows that melting of wax is a physical change.

Burning of candle also produces light and some gases like carbon dioxide. Hence, burning of wick of the candle is a chemical change.

Questions:  What happens when a piece of iron metal is placed in copper sulphate solution?(3 Marks)

(Ans)  A more reactive element displaces a less reactive element from its compound. For example when a piece of iron metal is placed in copper sulphate solution, then iron sulphate solution and copper metal is formed.Iron acquire redish brown colour that deposit  is copper.

Questions:   Which one is better technique to obtain sugar from sugar solution- crystallization or evaporation to dryness? 

(Ans)  Crystallization is a better technique than evaporation  because it has no dissolve impurities .that may left in evaporation  So Salt obtain from evaporation is mixed in boiled water . Then solution is filtered  to remove dissolved impurities . The filtrate is left undisturbed for few hour . Sodium chloride aggregate and form pure crystal of salt 

Long type questions                                      

Questions:  What is Valency?

Ans: Valency is the combining capacity of an atom. It is equal to the number of electrons the atom loses, or gains or shares when it combines with one or more atoms.   Depending on whether the atom loses, gains or shares electrons, the valency may be positive or negative or neutral respectively.   Example: Valency of sodium is + 1, because it can lose one electron. It is represented as Na⁺. Valency of oxygen may be - 2 if it accepts 2 electrons i.e., O^2-.

Questions: What is Chemical formula ?

Ans: The chemical formula of a substance is the symbolic representation of the actual number of atoms present in one molecule of that substance.  

Example 1: Formula of one molecule of oxygen is O₂. It shows that one molecule of oxygen is made up of 2 atoms of it.  

Example 2: Formula of one molecule of water is H₂O. It shows that one molecule of water is made up of 2 atoms of hydrogen and one atom of oxygen.  

 Example 3: Formula of one molecule of sulphuric acid is H₂SO₄. It shows that one molecule of sulphuric acid is made up of 2 atoms of hydrogen, 1 atom of sulphur and 4 atoms of oxygen.

Questions: What is radicals ?

Ans:  when the atoms of different elements combine in a group they are called radicals. They behave as a single unit and the valency of radicals is the overall net charge of the group. The radicals maintain their identity in the chemical changes but are incapable of independent existence  Hydroxide - OH^-   Sulphate - SO₄^-   Nitrate - NO₃^-   Sodium Na¹⁺ , Cu ²⁺ 

^{Negative radicals}

Positive Radicals 

Questions:  What is the difference between physical change and chemical change? Give example.

(Ans) The difference between physical change and chemical change is as follows-Physical change

(1) No new substance is formed. A substance undergoes a change in its physical properties.
(2) Physical change is generally reversible.
Example—Melting of ice, lighting of bulbChemical Change
(1) One or more new substances are formed by chemical reaction.
(2) Chemical change is irreversible.
Example—Burning of coal, photosynthesis

Questions:  How is alloy prepared? 

(Ans) An alloy is prepared by mixing various metals in molten state in required proportions and then cooling this mixture to the room temperature. The properties of alloys are different from the properties of the constituent metals, e.g., Stainless steel is made by mixing iron with carbon and metals like chromium, nickel and manganese. It does not rust like pure iron.If one of the metals in an alloy is mercury, it is called an amalgam

Questions:   Describe how crystals of copper sulphate are prepared?

(Ans) A cup full of water is taken in a beaker and a few drops of dilute sulphuric acid are added into it. The water is heated. When it starts boiling, copper sulphate powder is added slowly while stirring continuously till no more powder can be dissolved. The solution is filtered and allowed to cool down. Crystals of copper sulphate slowly form at the bottom of the beaker.

Class IX_Atoms and Molecules TIPS FOR EXAM & IMPORTANT POINTS TO LOOK AFTER AND SOME IMPORTANT Questions For PRACTICE

Consider the below mentioned terms/questions at the time of preparation.

• Name of scientists who established the two important laws of chemical combinations?

• Write the chemical formulae of the given compounds:

       (i) Copper sulphate sodium carbonate

       (ii) Barium chloride sodium sulphate

       (iii) Lead nitrate sodium chloride

• Concept of law of conservation of mass and law of chemical combination with examples

• E = mc² follows the law of conservation of mass or not

• Calculations based on numerical problems to make an agreement for the law of conservation of mass

• 2.8 gram of N2 gas was allowed to react with 0.6 gram of hydrogen gas to produce 3.4 gram of ammonia. Show that these observations are in agreement with the law of conservation of mass

• Postulates of Dalton’s atomic theory

• Law of definite proportion

• Which postulate of Dalton’s atomic theory is the result of the law of conservation of mass?

• Which postulate of Dalton’s atomic theory can explain the law of definite proportions?

• Full form of IUPAC

• Name of atoms and their symbols

• Homo atomic molecules and heteroatom molecules

• Concept of atomicity and its formula to calculate the same

• Definition of isotopes, isotones, and isobars with examples

• Identify the isotopes, isotones, and isobars from the given pairs

       a. (17Cl35, 17Cl37)

       b. (18Ar40, 20Ca 40)

       c. (6C13, 7N14 )

• Find the atomicity of chlorine if its atomic mass is 35.5 and molecular mass is 71

• Find the atomicity of ozone if its atomic mass is 16 and molecular mass is 48

• Concept of relative atomic mass and relative molecular mass

• Define 1 amu

• A very fine study about the mole concept. Different ways to calculate the number of moles

• Concept of ion formation and generation of positive and negative charges

• Cross valency concept to write the formula of compound

• Always focus on the concept given in your book rather than  different materials from different books or sites

Important Questions are as below:

Q. Magnesium and oxygen combine in the ratio of 3:2 by mass to form magnesium oxide. How much oxygen is required to react completely with 12 g of magnesium?

Q. Which postulate of Dalton’s atomic theory is the result of the law of conservation of mass?

Q. Which of the following statements is NOT true about an atom?

       (a) Atoms are the building blocks from which molecules and ions are formed.

       (b) Atoms cannot exist independently.

       (c) Atoms are neutral in nature.

       (d) Atoms combine together to form matter that we can see, feel, or touch.

Q. A sample of vitamin C is known to contain 2.58 ×1024 oxygen atoms. How many moles of oxygen atoms are present in the sample?

Q. If bromine atom is available in the form of, say, two isotopes 7935Br (49.7%) and 8135Br (50.3%), calculate the average atomic mass of bromine atom.

Q. Which has more number of atoms, 100g of N2 or 100 g of NH3?

Q. Calculate the relative molecular mass of water (H₂O)

Q. Calculate the formula unit masses of ZnO, Na2O, and K2CO3.

      [Given atomic masses of Zn = 65 u, Na = 23 u, K = 39 u, C = 12 u, and O = 16 u]

Q. Write the chemical formulae of the following.

       (a) Magnesium chloride

       (b) Calcium oxide

       (c) Copper nitrate

       (d) Aluminium chloride

       (e) Calcium carbonate.

b) Planaria
Ans-fragmantation, regeneration, transverse binary fission
c) Yeast
Ans-budding ,spore formation
d) Frog
Ans-Sexual
e)Rose
Ans-grafting, cutting
f) Bacteria
Ans-binary fission, spore formation

CLASS X REPRODUCTION VSA/ SA/LA QUESTIONS WITH ANSWERS..

VERY SHORT ANSWER TYPE QUESTIONS (1mark each)
1. Define reproduction.
Ans : It is the process of producing new organism of the same species by existing organisms of a species.
2. Define fertilization. Where the fertilization does takes place in human female?
Ans: in oviduct.
Ans: It is defined as the fusion of a male gamete( sperm) with a female gamete(ova) to form a zygote
during sexual reproduction.
The fertilization takes place in oviduct in human female
3. Name two type of reproduction. Ans-Two main type of reproductions is asexual reproduction and sexual
reproduction.
4. The anther contains: a...Sepal b. ovules c. carpel d.. Pollen grains
Ans –Pollen grains
5. What method will you use for growing jasmine and rose plant?
Ans: Artificial mode of vegetative reproduction-layering and grafting are use for growing jasmine and rose
plant.
6. Define menstruation.
Ans-The breakdown and removal of inner thick and soft lining of uterus along with blood vessels in the form
of veginal bleeding is called menstrual flow or menstruation.
7. Write the name of male and female reproductive part of a flower.
Ans: Male reproductive part is stamen, which consists of filament and anther. Female reproductive part is
carpel, which consists of ovary, style and stigma.
8. Define gestation period. What is the gestation period in human?
Ans—The time period from the development of foetus inside the uterus till birth is called gestation period. In
humans, the gestation period lasts for 9 months or 40 week or 280 days.
9. Why do testes in mammals descend in scrotum?
Ans-The location of the scrotum regulates the temperature of the testes because sperm formation requires
a lower temperature than the body temperature.
10. Name the type of fission carried out by Amoeba.
Ans-Amoeba reproduces by binary fission in which one cell divides into two daughter cells.
11. Name two sexually transmitted diseases.
Ans- Gonorrhea and syphilis.
12. What is vegetative propagation?
Ans-- The development of new plants from parts such as roots, stem and leaves, of the plant is called
vegetative propagation.
13. Name the male and female gonads and what are the products they produce.
Ans: Male gonads - Testes, Products-Hormone testosterone which stimulates the secretion of sperm from
testes.
Female gonads – ovaries, Products-hormones estrogen and progesterone, which stimulates the secretion
of eggs.
14. Which part of human female reproduction system is called ―birth canal‖ and the ―womb?
Ans –Vagina is called the birth canal and the uterus is called the womb
15. Write the full form of IUCD and AIDS,
Ans- (a) Intra Uterine Contraceptive Device (b) Acquired immune deficiency syndrome.
17. What is syngamy?
Ans: The fusion of one male gamete with an egg to form zygote is called syngamy.
18. What is advantage of fruit formation in plant?
Ans: Fruit formation helps in easy dispersal of seed.
19. What is ovulation?
Ans: The release of ovum or the egg from the ovary is called ovulation.
20. What is menopause?
Ans-The permanent stoppage of menstruation at age of 45-50 years is called menopause.
SHORT ANSWER TYPE QUESTIONS (Each of 2 marks)
1. What is the importation of DNA copying in reproduction?
Ans-DNA copying helps to pass on the parental body features to offspring’s. It produces
variations, which are useful for the survival of species over time.
2. Why is variation beneficial to the species but not necessarily for the individual?
Ans-Organisms are normally adopted to live in a particular kind of niche. In case of
alternation in the ecological conditions of that niche, the organisms would not be able to
survive. Only the variants’ the organisms resistant to changes would survive and grow
further. Thus variation is beneficial to the species not necessarily for the individual.
3.How does binary fission differ from multiple fission?
Ans-Binary fissions results in the formation of two equally sized daughter cells, whereas
multiple fission results in the formation of many daughter cells.
4. How will an organism be benefited if it reproduces through spores?
Ans-An organism if it reproduces through spores in the following ways:
a. Spores are formed in large number.
B.Spores have an outer thick wall that protect them in adverse conditions until they come in
contact with another moist surface and begin to grow.
5. Can you think of reasons why more complex organisms cannot give rise to new
individuals through regeneration?
Ans-More complex organisms cannot give rise to new individuals through regeneration
because:
i. There body is highly complicated.
ii. There are specific organ for specific functions.
iii. There is a labour division in the body of complex organisms.
iv. Regeneration is carried out by specialized cells which are not present in complex
organisms.
6. .Why vegetative reproduction is practiced for growing some type of plants?
Ans-Vegetative reproduction is practiced in some types of plants due the following reasons:
1. The plants which do not produce viable seeds are propagated by vegetative
propagation such as banana, orange and rose.
2. Plants raised by vegetative propagation bear flower and fruit earlier than
those produce from seeds.
3. Seedless fruits are produced by vegetative propagation.
7. Why is DNA copying an essential part of the process of reproduction?
Ans-a) DNA copying provides cellular apparatus in the daughter cells.
b)DNA copying is essential for obtaining exact body design.
c) It is essential for inheritance of features from parents to offspring.
8. . What are the changes seen in girl’s at the time of puberty?
Ans-Various changes take place in girl’s body at the time of puberty :
a)Thick hair growth in the arm pit and genital area.
b) Oily skin and appearance of pimples
c) breast size begins to increase
d) Girls begins to menstruates etc.
9. . What is the role of the seminal vesicles and the prostate gland?
Ans—The secretion of seminal vesicles activates and nourishes the sperms whereas the
secretion of prostate gland contributes the mortality and fertility of sperms.
10. How is the process of pollination different from fertilization?
Ans-Pollination is the process of transfer of pollen grains from anther to stigma whereas
fertilization is the process of fusion of male gamete with a female gamete to form zygote.
11.How does the embryo get nourishment inside the mother’s body?
Ans-The embryo gets nourishment inside the mother’s body through placenta.This tissue
contains villi on the embryo’s side and is surrounded by blood from the mother’s side.
Substances like glucose and oxygen pass from the mother’s blood to the embryo through
villi.
12.If a women is using copper –Twill it help in protecting her from sexually transmitted
diseases?
Ans-No, because copper-T helps in preventing pregnancy ,but not provide protection against
sexually transmitted diseases.
13.Show by a series of labeled diagram, the manner in which reproduction in Hydra.
Ans-Hydra reproduces by budding using the regenerative cells. A bud develops as a
outgrowth in hydra due to repeated cell division of specific site, when full mature, the bud
detaches from the parent’s body and develop into new individuals.
14.Describe regeneration. Fig-
Ans-It is ability of a fully differentiate organisms to give rise to new individual from its body
parts. For example-Hydra and Planaria. If Hydra is cut into two or more pieces grow into new
and complete Hydra .This is known as regeneration.
15.Define the terms unisexual and bisexual flowers by giving one example of each.
Ans-Unisexual flower means flower which contain only one sex organs either stamen or
carpel but not both.ex-papaya, watermelon. Bisexual flower means flowe which contain both
stamen and carpels. Ex- hibiscus.
16.Leaves of the bryophyllum fallen on the ground produce new plants whereas the leaves
of rose donot. Why?
Ans-Leaf of bryophyllum show vegetative propagation in plants where a part of the body
becomes detached and develop into a new supporting plant..Here leaves of bryophyllum
having plantlets along the margine of the leaf, while this structure is absent in rose plant.
Q.17. Why does menstruation occur?
Ans. The removal of the inner, thick and soft lining of the uterus along with its blood vessels
as well as blood in the form of vaginal bleeding is called menstruation. In humans after a girl
attains puberty ovaries start producing mature ovum every month and also uterus lining gets
thickened to receive zygote. When the uterus does not receive any zygote then
menstruation occurs to excrete lining of uterus and degenerating ovum.
Q. 18. What are the different methods of contraception?
Ans. The different methods of controlling the child birth are –
(1) Hormonal methods: Various kinds of pills containing hormones which prevent the release
of egg from the ovary, without interfering with other phases of menstrual cycle, are taken
orally.
(2) Barrier method: These are the physical and chemical barriers which prevent the sperms
meeting the egg. Physical devices such as condoms, diaphragms and cervical caps are
used.
(3) Intrauterine Devices: Commonly called as I.U.Ds, they are the devices made of plastics
and come in different shapes. The most commonly among these is copper- ‘T’. These
devices are placed inside the uterine cavity and permanently kept there. It prevents the
implantation in the uterus.
(4) Surgical methods. The surgical methods are safe and permanent.
(i) Vasectomy. In this operation, a small piece of vas deferens is cut and removed and the
two ends of the cut vas deferens are tied.
(ii) Tubectomy. In this operation, fallopian tubes are cut, tied with nylon thread to close the
passage, which prevents the passage of eggs.
Q.19. How are the modes of reproduction different in unicellular and multicellular organisms?
Ans. Unicellular organisms contain only one cell so they reproduce by asexual reproduction.
Example: budding, binary and multiple-fission are some of the asexual methods. Multicellular
organisms which have complex body designs (have organ systems) ex. Humans, animals,
plants reproduce sexually.
Q.20. How does reproduction help in providing stability to populations of species?
Ans. Reproduction is the process through which an organism produces new organism of its
own kind.
It is necessary because in a population organisms die due to old age or disease thus it
keeps the number of organisms in a population constant and provides stability to a
population.
SHORT ANSWER TYPE QUESTIONS(3 Marks each)
1.What is advantages of sexual reproduction over asexual reproduction?
Ans-a) Sexual reproduction plays a prominent role in evolution of new species whereas
asexual reproduction does not.
b)Sexual reproduction provides opportunity for new combination of gens and thus causes
genetic variation. This is not applicable by asexual reproduction.
2.What are function performed by testis in human beings.?
Ans-The testis produces sperms and secrets the hormone testosterone ,which regulates the
formation of sperms and brings about changes in appearance seen in boys at the time of
puberty.
3.Why does menstruation occur?
Ans- Every month as one of the ovaries releases ovum,the uterine wall thickens and
prepares itself for receiving the developing zygote.If the fertilization of the ovum does not
take place, the lining of uterine wall slowly breaks and menstruation occurs.
4. Differentiate between natural and artificial vegetative propagation.
Ans
Natural propagation Artificial propagation
1. New parts are obtained by 1.New plants obtained from vegetative propagation
Parts of the old plants. Like cutting, layering and grafting artificially.
2.Better quality of plant cannot 2.Better quality of the plant can be maintained.
be develop.
5.Draw a diagram of a flower to show its male and female reproductive parts. Label on it : a.-
the ovary b- the anther c- the filament d- the stigma .
Ans- fig—
6.Desribe the fertilization in flower .
Ans—Pollination is followed by fertilization in plants after pollen lands on the sutable stigma,
it has to reach the female germ cells in the ovary. The pollen tube grows out of the pollen
grain through the style to reach the ovary . After fertilization zygote divide several times to
form an embryo within the ovule .The ovules than develop a tough coat and gets converted
into seed. The seed contain a future embryo which converted into a seedlings.
7. What is meant by pollination? How it takes place?
Ans—It is transfer of pollen grains from the anther of the stamen to stigma of a carpel .The
pollen grains are transferred by many agents like insects, birds mans wind etc.
8.What is ‘vegetative propagation’? Write two examples where it is used. State two reasons
of practicing vegetative propagation for giving same types of plants.
Ans-Vegetative reproduction means production of new plants from the parts of the old plant
like stem roots and leaves without the help of reproductive organs.
Reason of practicing vegetative propagation-a .It is cheaper, easier more rapid method of
propagation. b . The traits of a parents plants are preserved by vegetative priopragation.
9. Illustrate the following with the help of suitable diagram:
a) Regeneration in Planaria.
b) Budding in Hydra.
Ans-Fig
Regeneration is ability of a fully differentiated organism to give rise to new individual from its
lost body parts. For ex-in Planaria ,it can be cut into number of pieces and each pieces
grows into complete organism. In Budding a small part of the body of the parent grows out
as a ‘bud’ which than detaches and become a new organism. For ex- In Hydra bud develop
as an outgrowth due to repeated cell division, when fully mature it detach from parent body
and develop into new individual.
10. .Give differences between asexual and sexual reproduction.
Ans-
Asexual Reproduction Sexual Reproduction
1.Only one parent is involved in asexual
reproduction.
1.Two organisms, one male and one female
are involved.
2. Gametes are not formed. 2. Gametes are formed .
3. Offspring’s formed are genetically identical
to the parent.
Offspring’s formed are genetically different
from their parents.
11. Give a short account of menstruation in females.
Ans—The breakdown and removal of the inner thick and soft lining of the uterus along with
its blood vessels in the form of vaginal bleeding is called menstruation. The series of cyclic
changes involves the formation of follicles, preparation of uterine wall for implantation
,ovulation ,secretion of nutritive fluid by mature endometrium. In absence of fertilization , the
uterine wall collapse and leads to discharge of blood and mucus with unfertilized egg.
12. Describe why :
a) Scrotum remains outside the body of human males ?
b) Some plants are propagated only by vegetative propagation ?
Ans—a) Scrotum are located outside the body of human male because sperm formation
requires lower temperature than the normal body temperature .
b) Some plants are propagated only by vegetative propagation because they have lost the
capacity to produce seeds .ex-Banana, orange, Jasmine etc.
13. How does reproduction help in providing stability to populations of species ?
Ans-Niche is a place or position suitable for an organism .The DNA copying during
reproduction helps in the maintenance of the body design features that allow the organism to
use the particular niche.This is how reproduction helps in providing stability to population of
species.
LONG ANSWER TYPE QUESTIONS (5 Marks Each )
14.Draw a diagram of human female reproduction system.
.Draw a labeled diagram of longitudinal section of pistil of flower showing germination of
pollen grains on the stigma.
Ans-Fig
16. .Describe a neat and well labeled diagram of male reproductive system in human.
Ans
17. Describe the changes taking place in female reproductive organs every month
Or What will happen if ovum is not fertilized? Describe the events in a sequence wise
manner.
Or Why does menstruation occur?Ans-Cyclic changes taking place in the reproductive
organs of non pregnant women are termed as menstrual cycle. They take place if the ovum
is not fertilized .I mportant events in sexual cycle of females:
Ovulation-Release of mature ovum from the ovary.
Menstruation-Degeneration and removal of inner thickened lining of uterus along with blood
after every 28 days, through the vaginal canal Both these events stop if pregnancy occurs
and are resumed after the child birth: If fertilization does not occur, both the processes keep
occurring periodically every month.
18.How do following organisms reproduce?
a)Amoeba
Ans-binary fission
b) Planaria
Ans-fragmantation, regeneration, transverse binary fission
c) Yeast
Ans-budding ,spore formation
d) Frog
Ans-Sexual
e)Rose
Ans-grafting, cutting
f) Bacteria
Ans-binary fission, spore formation

CLASS X - REPRODUCTION INTEXT AND EXERCISE QUESTIONS WITH ANSWERS..

REPRODUCTION INTEXT AND EXERCISE QUESTIONS WITH ANSWERS..
Q. 1. What is the importance of DNA copying in reproduction?
Ans. The creation of a DNA copy is essential to produce organisms which are similar to their
parents.
As copying of DNA brings some variations each time, the surviving cells are similar to parent
cell but subtly different from each other. This tendency for variation during reproduction brings
variations among the individuals of the same species.
Q. 2. Why is variation beneficial to the species but not necessarily for the individual?
Ans. Niches are well-defined places in the ecosystem where population of organisms lives in. If
population of reproducing organisms is suited to a particular niche and if that niche is drastically
altered or destroyed, because of uncontrollable reasons like temperature changes, water level
changes etc, the population can be wiped out. However, if some variations are present in a few
individuals in these populations, there will be chances for their survival. The surviving individual
can further reproduce and develop a population as per the changed niche. In this way,
variation is beneficial to the species but not necessarily for the individual
Q. 3. How does binary fission differ from multiple-fission?
Ans : Binary Fission
1. Nucleus divides into two daughter nuclei.
2. Constriction is formed in the cell after nuclear division.
3. Only two daughter cells are produced
4. It takes place in favourable conditions.
 Multiple fission
1. Nucleus divides into many daughter nuclei.
2. Division of cytoplasm occurs very late thus many cells are
produced simultaneously.
3. Many new daughter cells are produced.
4. It takes place in adverse conditions.
Q.4 How will an organism be benefited if it reproduces through spores?
Ans. Spores have a hard outer covering that is able to withstand adverse conditions of high
temperature, shortage of water and food. So if an organism reproduces through spore
formation it can easily withstand these adverse conditions.
Q.5. Can you think of reasons, why more complex organisms cannot give rise to new
individuals through regeneration?
Ans. Higher complex organisms cannot give rise to new individuals through regeneration
because:
1. Higher organisms have very complex body designs i.e. they show the following hierarchy of
organization cell-tissue-organ-organ system.
2. Higher organisms do not have special calls which help in regeneration of lost part.
Q.6. Why is vegetative propagation practiced for growing some types of plants?
Ans. Vegetative propagation is used to grow some plants such as banana, orange, rose etc
because these plants have lost the capacity to produce viable seeds.
Q. 7. Why is DNA copying an essential part of the process of reproduction?
Ans. The creation of a DNA copy is essential to produce organisms which are similar to their
parents.
As copying of DNA brings some variations each time, the surviving cells are similar to but
subtly different from each other. This tendency for variation during reproduction brings variations
among the individuals of the same species.
Q.8. How is process of pollination different from fertilization?
 Pollination
1. It is the process of transfer of pollen grains from anther to stigma.
2. Through this process pollen grains carrying male nucleus reach to stigma (part of female
reproductive system).
Fertilization
1. It is the process of fusion of male and female nucleus.
2. Through this process diploid zygote is formed which develops into a seed.
Q.9. What is the role of seminal vesicles and prostate gland?
Ans. Secretions of seminal vesicle and prostate gland provide nutrition and motility to the
sperms.
This secretion also helps in transport of sperms.
Q.10. What are the changes seen in girls at the time of puberty.
Ans. Following changes come in girls at the time of puberty:
1. Increase in the breast size of the girls. 2. Growth of hair under the arm-pits and pubic hair
starts.
3. Menstruation cycles commence. 4. Skins become oily.
Q.11. If a woman is using a copper-T, will it help in protecting her from sexually transmitted
diseases?
Ans. No, because copper-T will not prevent contact body fluids. Thus it will not protect her from
sexually transmitted diseases.
Q.12. What are the advantages of sexual reproduction over asexual reproduction?
Ans. Following are the advantages of sexual reproduction over asexual reproduction:
i. In sexual reproduction cells with different genetic material fuse. Thus it leads to mixing of
different characters and new characters emerge.
ii. Accumulation of variations leads to formation of new species.
iii. Sexual reproduction has speeded up the process of evolution.
Q.13. What are the functions performed by the testis in human beings?
Ans. Testis is the male reproductive organs in humans. Testis produces sperms (haploid male
gamete) which contain haploid set of chromosomes of father.
Q.14. Why does menstruation occur?
Ans. The removal of the inner, thick and soft lining of the uterus along with its blood vessels as
well as blood in the form of vaginal bleeding is called menstruation. In humans after a girl
attains puberty ovaries start producing mature ovum every month and also uterus lining gets
thickened to receive zygote. When the uterus does not receive any zygote then menstruation
occurs to excrete lining of uterus and degenerating ovum.
Q. 15. What are the different methods of contraception?
Ans. The different methods of controlling the child birth are –
(1) Hormonal methods: Various kinds of pills containing hormones which prevent the release of
egg from the ovary, without interfering with other phases of menstrual cycle, are taken orally.
(2) Barrier method: These are the physical and chemical barriers which prevent the sperms
meeting the egg. Physical devices such as condoms, diaphragms and cervical caps are used.
(3) Intrauterine Devices: Commonly called as I.U.Ds, they are the devices made of plastics and
come in different shapes. The most commonly among these is copper- ‘T’. These devices are
placed inside the uterine cavity and permanently kept there. It prevents the implantation in the
uterus.
(4) Surgical methods. The surgical methods are safe and permanent.
(i) Vasectomy. In this operation, a small piece of vas deferens is cut and removed and the two
ends of the cut vas deferens are tied.
(ii) Tubectomy. In this operation, fallopian tubes are cut, tied with nylon thread to close the
passage, which prevents the passage of eggs.
Q.16. How are the modes of reproduction different in unicellular and multicellular organisms?
Ans. Unicellular organisms contain only one cell so they reproduce by asexual reproduction.
Example: budding, binary and multiple-fission are some of the asexual methods. Multicellular
organisms which have complex body designs (have organ systems) ex. Humans, animals,
plants reproduce sexually.
Q.17. How does reproduction help in providing stability to populations of species?
Ans. Reproduction is the process through which an organism produces new organism of its own
kind.
It is necessary because in a population organisms die due to old age or disease thus it keeps
the number of organisms in a population constant and provides stability to a population.
Q.18 What could be the reasons for adopting contraceptive methods?
Ans. Following are some reasons for adopting contraceptive methods:
1. For population control. 2. To prevent spread of STDS (sexually transmitted diseases).