EXPLANATIONS
Objective Questions
12. (c) The given flow chart shows the movement and fate of egg
1. (a) Statements I, II and IV are correct, whereas statement
in female body.
III is incorrect. Incorrect statement can be corrected as
When egg gets fertilised it forms zygote which develops
The process of copying of DNA will have some variations
into embryo. Early embryo gets implanted leading to
pregnancy (X).
each time. As a result, the DNA copies generated will be
similar, but may not be identical to the original.
When egg does not get fertilised, it degenerates and passes
out as menstrual discharge through vagina therefore leads to
2. (d) The given diagram shows how Leishmania reproduces
menstruation (Y).
through binary fission to produce two daughter cells.
13. (c) Option (c) is correct labelled part with its function.
3. (b) Asexual reproduction in Hydra and yeast, takes place by
budding.
(iii) is urethra, it is a common passage for both the sperm
and urine.
4. (c) Planaria is a flatworm which possesses high regeneration
Other options are incorrect labelled parts with their
ability. If its body somehow gets cut into pieces, then each
functions and can be corrected as
piece can regenerate into a complete organism by growing
the missing parts.
(i) is prostate gland, its secretion form 20-30% of
semen which is essential for the mobility of sperms.
5. (d) The Planaria reproduces through regeneration method,
(ii) is penis, it transfers sperm into the vagina of female
therefore all the cut parts (i.e. P, Q, R and S) of the Planaria
during copulation.
will regenerate to form complete worms.
(iv) is testis, it produces sperms and a male sex hormone
6. (a) A is Bryophyllum, it reproduces by vegetative
called testosterone.
propagation.
14. (b) Option (b) contains male reproductive organs of humans.
B is Plasmodium, it reproduces by multiple fission.
The male human reproductive system consists of seminal
7. (a) The given diagram shows various parts of pistil.
vesicle, prostate gland, testis, vas deferens, urethra, penis,
A is stigma, it helps in receiving the pollen grains during
scrotum, etc., whereas uterus, vagina and cervix are parts of
pollination.
female reproductive system.
B is style, the pollen tube grows out of the pollen grain and
15. (d) Regulation of metabolism for body growth is not a
travels through the style.
function of testosterone (but by thyroid hormones).
C is ovary, it ripens as fruit after the process of fertilisation.
16. (a) Vasectomy is a minor surgery to block sperm
D is ovule, it is the female gamete or female germ-cell of
from reaching the semen that is ejaculated from the
the flower.
penis.
8. (d) Option (d) is correct labelled part with its
The labelled part X in the given diagram is vas deferens.
functions/characteristics.
Once vas deferens are cut, sperms cannot get into the
D is filament, it lifts anther to disperse pollen grains.
semen or out of the body. Hence, ejaculation of sperms
Other options are incorrect labelled parts with their
stops.
functions characteristics and can be corrected as
17. (b) The diseases which are spread by sexual contact with an
A is anther, it is a site of pollen formation.
infected person are called Sexually Transmitted Diseases or
B is style, it lifts stigma to receive pollen.
STDs, e.g. gonorrhoea, syphilis and AIDS. Hepatitis is a
C is ovary, it contains ovule which develops into seeds while
water-borne viral disease which affects liver. It is not a sexual
ovary forms the fruit.
transmitted disease.
9. (c) The stamen (male part) contains a swollen topmost part
called anther which contains male gametes, i.e. pollen
18. (a) Both A and R are true and R is the correct explanation of A.
grains. Ovary (female part) makes ovules (female gametes)
The new individuals produced by asexual reproduction are
and stores them.
always genetically identical to each other and their parents,
hence are known as clones.
10. (c) The primary reproductive organs or gonads consist of the
ovaries and testes. All other organs, ducts and glands in the
19. (d) A is false, but R is true because
reproductive system are considered as secondary or
In males, urethra forms the common passage for both the
accessory reproductive organs. So, ovary is not a secondary
sperms and urine. whereas ureters are tubes that propel
reproductive organ.
urine from the kidneys to the urinary bladder. It never
carries sperms.
11. (b) The correct matches are as follows
20. (a) Both A and R are true and R is the correct explanation of A.
A Oviduct or Fallopian tubes are the site of fertilisation.
Vagina is called as birth canal, because the fully matured baby
B Ovary releases one mature egg (ovum) every month.
passes through the vagina during birth.
C Vagina, in absence of fertilisation, the lining of uterus
21. (a) Both A and R are true and R is the correct explanation of A.
slowly breaks and comes out through the vagina as
Since, the ovary releases one egg every month, the uterus
blood and mucus.
also prepares itself every month to receive a fertilised egg.
D. Lining of uterus is site for implantation of embryo.
Its lining become thick and spongy to nourish the
Thus, option (b) is correct.
developing embryo.
22. (d) A is false, but R is true because
However, if some variations are present in few individuals, it
would help them to colonise other habitats and survive. But, if
AIDS (Acquired Immuno Deficiency Syndrome) is caused
variations are present in a single organism, there would be a
by HIV (Human Immunodeficiency Virus), so it is a viral
very little chance for it to survive and species is lost forever.
disease. The virus attacks the body’s immune system and
suppresses it.
Hence, variation is beneficial to the species, but not
necessary for the individuals.
23.
(i)
(a) Stems are more suitable for vegetative propagation
due to the presence of nodes in them.
3. Clones are the offsprings produced by one parent through
(ii)
(d) Some plants undergo vegetative propagation such as
asexual reproduction. These are genetically identical to the
potato (through nodes), sugarcane (through stem),
parent. The clones possess exact copies of the DNA of their
Bryophyllum (through leaves). Wheat plant does not
parent and hence show remarkable similarity to the parent
and to one another.
undergo vegetative propagation and is grown by sowing
seeds.
4. When the colony of yeast is in water, it does not get
(iii)
(c) In grafting, the cut stem of a rooted plant is called
nutrition. Sugar solution, on the contrary provides nutrition.
stock and the cut stem of another plant without roots is
As the yeast gets nutrition and thus energy, it grows and
called scion.
begins to produce buds. This is why colonies of yeast fail to
multiply in water, but multiply in sugar solution.
(iv)
(d) The process of growing many plants from one plant
by man-made methods is called artificial vegetative
5. Multicellular organisms like filamentous algae (Spirogyra)
propagation of plants. The new plants produced by this
and sea animal called sea anemone on maturation breakup
method have similar characterstics as their parent
into two or more small fragments or pieces. Each fragment
plant. Many seedless plants can grow by this method.
subsequently grows to form a complete new organism. This
Hence, all the given statements are correct about
type of asexual reproduction is known as fragmentation.
artificial vegetative propagation.
6. Two advantages of vegetative propagation are as follows
Thus, option (d) is correct.
(i) Vegetative reproduction is easier and faster methods of
(v)
(c) Grafting is a most suitable method of artificial
reproduction.
propagation for combining the desirable characters of
(ii) It is useful in those plants/animals, which cannot
two plants together in a single plant.
reproduce sexually.
24.
(i)
(a) A is umbilical cord, it is a narrow tube-like
7. Layering is a type of vegetative propagation, e.g. lemon,
structure that connects the developing baby to the
rose, jasmine, strawberry, etc., can produce new plant by the
placenta.
process of layering.
C is placenta, it is an organ attached to the lining of
8. The main difference between sexual and asexual
the womb that delivers oxygen and nutrients to the
reproduction involves the production and union of gametes
growing baby.
in the process of fertilisation in sexually reproducing
(ii)
(b) Sex of a child is always determined by the type of
organisms which do not occur in asexual mode of
sex- chromosomes received by the father. Male
reproduction.
produces two types of sperms, either having
Sexual reproduction is considered to be superior over
X-chromosome or Y-chromosome.
asexual reproduction as it leads to variations, while asexual
(iii)
(c) Placenta is embedded in the uterine wall.
reproduction does not induce variations among progeny
(iv)
(c) Copper-T is an IUD (Intrauterine Device). It
individuals.
releases copper ions which are toxic to the egg and
Advantages of variations in individuals are
sperms. It stops sperm from fertilising the egg.
(i) It brings adaptation in individuals.
Therefore, it prevents pregnancy for upto 10 years.
(ii) It helps in the survival of species.
(v)
(d) Oviduct also known as Fallopian tube, is the site of
(iii) It is the basis of evolution.
fertilisation, where male and female gametes fuse to
Hence, the species that reproduce through sexual
form zygote. So, union of male and female takes place
reproduction have better chances of survival.
in oviducts.
9. The number of chromosome in the female gamete would
Subjective Questions
be same as that in the male gamete, i.e. it will have 24
1. The importance of DNA copying during reproduction are
chromosomes. The number of chromosome in the zygote
(i) It is responsible for the transmission of parental
would be double the number present in the gamete and
characteristics to the offsprings.
hence, it would be 48.
(ii) During DNA copying in reproduction, the changes
10. Pollination is transfer of pollen grains from anther to the
occur due to the inheritance of traits from both the
stigma of a flower. It is of two types
parents. This leads to certain genetic variations, which
(i) Self-pollination Transfer of pollen from the stamens of
are useful for the evolution of species over a period of
a flower to the stigma of the same flower or on the
time.
stigma of other flower of the same plant.
2. Variations allow organisms to exist in diverse habitats or
(ii) Cross-pollination Transfer of pollen from the stamens of
niches. In its absence, a species may remain restricted to a
a flower to the stigma of different flower of different plant
particular area. If this area gets drastically altered due to various
of same species.
natural or man-made causes, the species may be wiped out.
11. A bisexual flower has the male as well as female
Hence, fertilisation cannot take place in flowers if pollination
reproductive organs. If the young stamen (i.e. male unit) is
does not occur due to the absence of pollen tube (i.e. the male
removed artificially, the flower still has its pistil (i.e. female
gamete).
unit) intact. Therefore, cross-pollination can occur.
16. General growth refers to different types of developmental
When the pollen grains from the anther of another flower
process in the body like increase in height, weight gain,
are transferred to the stigma of this flower with the help of
changes in shape and size of the body. During this phase, the
pollinating agents such as insects, bees, wind and water, it
reproductive organs develop at a slower rate.
causes cross-pollination. After the pollen grains fall on
During sexual maturation, the changes that occur prepare
stigma, the next step is fertilisation, followed by formation of
the body for sexual reproduction. These are specific changes
fruits and seeds.
reflected at puberty like cracking of voice, new hair patterns,
12. Stamens and carpels (pistils) are the reproductive organs of a
development of breast in female, etc.
flower, i.e. organs by which sexual reproduction in floral
17.
plants takes place.
Oviduct or
Fallopian tube
Most plants have both male and female reproductive organs
in the same flower and are known as bisexual flowers, e.g.
Ovary
Uterus
lily, rose, etc., while others have either male or female
reproductive parts in a flower known as unisexual flowers,
Cervix
e.g. papaya, watermelon, etc.
13.
(i)
Variations appear among the progeny formed by sexual
Vagina
reproduction due to the following reasons
(a) Sexual reproduction results in new combinations of
Female reproductive system
genes that are brought together during the formation
(i) Ovum is produced by ovaries which are paired,
of gametes by meiotic divisions (I and II).
oval-shaped organs.
(b) The combination of two sets of chromosomes, one
(ii) Oviduct or Fallopian tubes are the site of fertilisation.
between the homologous chromosome arms set from
They have funnel-shaped opening near ovary and carry
each parent during zygote formation, leads to
ova or egg from ovary to uterus.
variation within a species.
(iii) Implantation refers to embedding of the embryo in the
(ii)
(a) A-Pollen grain
thick lining of uterus.
(b) Pollen grain reaches part B, i.e. stigma by
18. Ovary in females is responsible for the production of female
pollinating agents such as insects, wind, water, etc.
gametes (ova) and also produces female sex hormones, i.e.
This process is known as pollination.
oestrogen and progesterone.
(c) Part C is pollen tube. It allows the passage for the
19. The absence of menstrual cycle may be the first indication of
male gametes to reach the ovary having female
pregnancy in a woman.
gamete for fertilisation.
20. If the egg is not fertilised, it lives for about one day. Since,
(d) Part D, i.e. female gamete or egg cell that forms
the ovary releases one egg every month, the uterus also
zygote after fertilisation.
prepares itself every month to receive a fertilised egg. Its
14. (i)
(a) Pollen grain
lining becomes thick and spongy, which is required for
nourishing the embryo. If fertilisation, however, does not take
(c) Stigma
place this lining is not needed in the absence of fertilisation
and it slowly breaks and comes out through the vagina as
(b) Pollen tube
blood and mucus. This cycle takes place roughly every
month and is known as menstruation cycle and usually lasts
for about 2-8 days.
21. The embryo gets nutrition from the mother’s blood with the
help of a special tissue called placenta. This is a disc-like
(d) Female
tissue which develops between the uterine wall and embryo.
germ cell
As mother eats, the food passes through the digestive system
where it breaks down into small particles. These nutrients
(ii)
The pollen tube takes its origin from intine of pollen
travel through the mother’s bloodstream and get exchanged
grains. It grows through the style and reaches the
with the bloodstream of foetus through placenta.
micropyle of ovule. It carries male nuclei to the ovule
22. The umbilical cord contains blood vessels which supply
for fertilisation.
blood between the foetus and the placenta.
(iii)
(a) Ovule develops into seed.
23. Testes are located outside the abdominal cavity because
(b) Mature ovary develops into fruit.
sperm formation requires a lower temperature than the
15. In a flower, fertilisation requires both male and female
normal body temperature.
gametes. So, it is necessary that the male gamete reaches the
24. Path of sperm during ejaculation Formation of sperms take
female gamete. This can happen when the pollen grains are
place in testis. Sperms come out from testis into the vas
transferred to the stigma through any means of pollination.
deferens. It then unites with another tube called urethra
coming from the urinary bladder. Along the path of vas
(iv) Surgical method for permanent contraception.
deferens, glands like the prostate and the seminal vesicle
Mechanical Barrier There are a number of methods that
add their secretion, so that sperms are in fluid medium to
create barrier between sperm and egg
make their transport easier. This fluid also provides nutrition.
Some of them are as follows
Glands associated with male reproductive system are
Condom It is a fine rubber balloon-like structure worn over
(i) Testis It secretes the male sex hormone, testosterone.
the penis during sexual intercourse. Semen is collected in it
(ii) Prostate Gland It makes the semen medium alkaline.
and not discharged into the vagina. This method also
(iii) Cowper’s Gland It secretion of this gland lubricates
prevents the spread of STDs like AIDS, syphilis, etc.
the urethra before ejaculation.
Diaphragms or Caps It can be fitted in the cervix of a
(iv) Seminal Vesicle It adds fluid content to semen.
woman to prevent semen from reaching the Fallopian
tube.
25. The ratio of chromosome number between egg and its zygote
32. All the living organisms need energy for their survival and
is 1 : 2. An egg is a female gamete and it has haploid number of
growth. This energy is obtained from various life processes
chromosomes. During fertilisation, it fuses with male gamete
(also having haploid number of chromosomes) to form a zygote
such as nutrition, excretion and respiration.
Thus, these phenomena are essential for the survival of an
which now has diploid number of chromosomes.
individual. Compared to these life processes, reproduction
Sperms and eggs are genetically different in terms of nature
is not essential for survival of an individual.
of sex chromosome. The sperm contains either X or
It is basically important for continuity of the generation of an
Y-chromosome, whereas an egg will always have an
organism or species as DNA copying during reproduction
X-chromosome.
helps to produce similar individuals as their parents to
26. Two methods of contracting an STD other than the sexual
maintain stability of a species.
contact are as follows
33. A species occupies a well-defined niche in an ecosystem,
(i) Sharing needles with an infected person.
using its ability to reproduce. During reproduction, copies of
(ii) Transfusion of STD unscreened blood.
DNA pass from one generation to the next. This copying of
27. People can practice safe sex by using condoms as it acts as
DNA takes place with consistency in reproducing organisms
barrier method of contraception and does not allow entry of
and this is important for the maintenance of body design
semen into vagina. Therefore, prevent STDs and avoid
features (physiological as well as structural) which allows the
chances of pregnancy.
organism to use that particular niche. Reproduction is
therefore, linked to the stability of population of a species.
28. No, copper-T does not prevent the transmission of sexually
transmitted diseases. Copper-T only prevents implantation.
34.
(i)
(a) Planaria—Regeneration
The only safe method that can be used to prevent the
(b) Hydra—Budding
transmission of sexually transmitted diseases is condoms.
(c) Rhizopus—Sporulation
29. Family planning refers to the regulation of conception by the
(ii) The leaves of Bryophyllum bear vegetative adventitious
use of contraceptive methods or devices to limit the number
buds which on separation can give rise to new plants.
of offspring.
35. Stamens and carpels are the reproductive parts of a flower.
The methods used to prevent the occurrence of pregnancy
Stamen is the male reproductive part of the flower.
are called contraceptive methods. These can be barrier,
Anther is a bilobed structure containing two pollen sacs
hormonal, chemical and surgical methods.
present at tip of stamen. These produce pollen grains that
30.
(i) Use of a condom is beneficial for both the sexes involved
are yellowish in colour.
in a sexual act. It is because of the following facts
Carpel (Pistil) is the female reproductive part, which is
(a) It prevents pregnancy which is not desired by a
present in the centre of the flower.
couple.
It comprises of three parts
(b) It saves both the partners from sexually transmitted
(i) Stigma It is the terminal part of carpel which may be
diseases like AIDS, etc.
sticky. It helps in receiving the pollen grains during
(ii) Oral contraceptives are the hormonal pills which are
pollination.
taken by the females after their menstruation ends up.
(ii) Style It is the middle elongated part of carpel. It helps in
It is taken for 21 days daily. It changes the cyclic events
the attachment of stigma to the ovary.
of ovulation, etc. So, mature ovum is not available for
(iii) Ovary It is the swollen bottom part of carpel. It contains
fertilisation.
ovules having an egg cell (female gamete).
(iii) Sex selective abortion means if the foetus is female, it is
killed and extracted. This creates an imbalanced in the
Stigma
Anther
society by disturbing the sex ratio.
Style
Filament
31. Ways to avoid pregnancy are called contraceptive methods.
Pistil
Petal
It includes a number of ways such as
(i) Mechanical barrier, e.g. condom.
Ovary
Sepals
(ii) Drugs (oral pills for females).
(iii) IUCD, e.g. copper-T.
Longitudinal section of flower
Fertilisation is the process of fusion of male germ cells with
The pollen grain is transferred from the stamen to the stigma. It
the female gametes. It gives rise to a zygote. As soon as the
is transferred of pollen occurs in the same flower, it is referred
pollen lands on suitable stigma, it reaches the female germ
to as self-pollination.
cells in ovary. This occurs via pollen tube. The pollen tube
On the other hand, if the pollen is transferred from one flower
grows out of the pollen grain, travels through the style and
to another, it is known as cross-pollination. After the pollen
finally reaches the ovary.
lands on a suitable stigma, it has to reach the female germ cells
36. The transfer of pollen grains from the anther of the stamen
which are present in the ovary.
to the stigma of a flower is termed as pollination. There are
For thus, a tube grows out of the pollen grain and travels
two types of pollination
through the style to reach the ovary.
(i) Self-pollination The pollen from the stamen of a
Pollen grains
flower is transferred to the stigma of the same flower
Stigma
or another flower on the same plant.
Male germ cell
(ii) Cross-pollination The pollen from the stamen of a
Pollen tube
flower is transferred to the stigma of another flower of
different individual of the same species.
The pollen grains can be transferred by various agents like
Ovary
wind, water, insects and animals. As soon as the pollen
Female
lands on suitable stigma, it reaches the female germ cells in
germ cell
ovary. This occurs via pollen tube.
The pollen tube grows out of the pollen grain, travels
Germination of pollen on stigma The male germ cell
through the style and finally reaches the ovary where it
produced by pollen grain fuses with the female gamete precut in
fuses with female gamete (ovule) to give rise to zygote.
the ovule. This fusion of germ cells is called fertilisation and
Hence, pollination is followed by fertilisation in plants.
gives rise to the zygote.
37. Distinguishes between pollination and fertilisation are as
After the fertilisation, the zygote divides several times to form an
follows
embryo within the ovule. The ovule develops a hard coat and is
gradually converted into a seed. The ovary grows rapidly and
Pollination
Fertilisation
ripens to form fruit. Meanwhile the petals, sepals, stamens, style
It is the transfer of pollen grains It is the fusion of male and
and stigma may shrivel and fall off.
from anther to the stigma.
female gametes.
39.
(i) A-Ureter
B-Seminal vesicle
It is a physical process.
It is a biological process.
C-Urethra
D-Vas deferens
(ii) Testosterone hormone is secreted by testis. It controls
The site of fertilisation is ovule in the ovary.
spermatogenesis (formation of sperm) and secondary
The product of fertilisation is a zygote.
sexual characters in male adolescents.
Pollen grain
(iii) Seminal vesicle B temporarily stores sperms.
Stigma
Urethra (C) It transports and releases urine and sperms
outside the body.
Male germ cells
40.
(i) The given figure represents the female reproductive
system. The parts labelled as A-E are
Pollen tube
A. Oviduct or Fallopian tube B. Ovary
C. Uterus
D. Cervix
E. Vagina
(ii) The prevention of pregnancies by using artificial method is
Ovary
called as contraception.
Advantages of using contraceptive measures are
(a) To control family size, population rise or birth rate.
Female
This is done by creating awareness about small
germ cell
families using contraceptive measures.
(b) To prevent chances of meeting female egg and male
Pistil showing pollen tube growth
sperm, thus preventing future unwanted pregnancies.
and its entry into ovule
(c) Use of barrier methods of contraception protects both
38. Stamen is the male reproductive part and it produces
the partners from contracting sexually transmitted
pollen grains. The ovary contains ovules and each ovule has
diseases like AIDS.
egg cell.
41. (i)
(i)
Prevention of unwanted pregnancies by using
contraceptives have shown the development of health in
Parts of female
Functions
women.
reproductive system
(ii)
Awareness of advantages of small families by using
(a) Ovaries
Produce thousands of ova or egg
contraceptives has led to economic growth of the family.
cells. Secrete female sex hormones
like oestrogen and progesterone.
45.
(i)
The ovules present in ovary of a flower develops into
seeds.
(b) Oviduct
Carries ova or egg from ovary to the
(ii)
Cotyledons of seed store food which fulfil the energy
(Fallopian tube)
uterus. It is the site of fertilisation.
requirement for seed germination.
(c) Uterus (Womb)
Here, the growth and development
(iii)
Radicle or future root of the plant emerges out the first
of foetus (embryo) take place.
Rhythmic contractions of the
from the germinating seed.
muscles in the uterus cause labour
(iv)
The process of developing seed into a seedling under
pain and childbirth.
appropriate conditions is known as germination.
(v)
All seeds need water, oxygen and proper temperature in
(ii) Structure of Placenta It is a disc between uterine wall
order to germinate.
and embryo which is embedded in the uterine wall. It
46.
(i)
The changes happening in adolescent boys and girls are
contains villi on the embryo's side of the tissue. On the
mother's side, blood spaces are present, which
The moustach starts appearing in boys and their voice
surrounded the villi.
becomes hoarse. There is onset of menstrual cycle in
girls and their mammary glands starts developing.
Functions of Placenta It provides a large surface area
for glucose and oxygen to pass from the mother to the
(ii)
Most rapid growth takes place within one year after the
embryo. It also removes the waste generated by embryo,
birth of a baby.
transferring it to mother's blood.
(iii)
The increase inheight ofgirlsceasesat the age of 15years.
42. Movement and fate of egg in female body
(iv)
In boys, significant spurt in height occurs at the age of
Eggs are produced in ovary
11-12 yrs.
Released in Fallopian tube
(v)
Both boys and girls grow body hair in their pubic area,
as well as under the arms and on the legs at the age of
adolescence.
If fertilised,
If unfertilised,
form zygote
degenerate
47.
(i)
The two main functions of the testes (F) are to produce
sperm and to produce the male sex hormones
Early embryo gets implanted
Passes out as
leading to pregnancy and
menstrual discharge
(testosterone). This makes the testis both an endocrine
foetus starts to develop
and exocrine gland.
(ii)
The sperm and eggs are genetically different terms of
43.
(i) Placenta is extremely essential for foetal development
nature of sex chromosome. The sperm contains either X
because it helps in nutrition, respiration, excretion, etc.,
or Y-chromosome whereas an egg will always have an
of the foetus through the maternal supply.
X-chromosome.
(ii) Blocking of vas deferens prevents passage of sperms,
(iii)
Semen is a fluid which contains sperm cells and
hence, there is no fertilisation so it prevents pregnancy.
secretion of accessory glands. It is a milky, viscuous fluid
(iii) Wind acts as a pollinating agent because it helps in
contains fructose, proteins and other chemicals for
transfer of light weighted pollen grains from anther to
nourishing sperms.
stigma of a flower.
(iv)
Vasectomy is a form of male birth control that cuts the
(iv) Condoms prevent entry of sperms into vagina, hence
supply of sperm to semen. It is done by cutting and
prevents pregnancy.
sealing the tubes that carry sperm, i.e. vas deferens (H).
(v) If Fallopian tube is blocked, sperm and egg do not meet or
(v)
Fusion of a sperm and an egg lead to the formation of
fuse and fertilisation does not take place.
a zygote. Therefore, a zygote is diploid in nature,
i.e. 2n, whereas a sperm and an egg are haploid in
44. Reproductive health is a state of physical, emotional, mental
nature, i.e. n. Hence, the ratio of chromosome number
and social well-being in relation to sexuality.
between an egg and its zygote is 1 : 2.
Significance of reproductive health in a society
48.
(i)
(a) AIDS (Acquired Immuno Deficiency Syndrome)
(i) It prevents the spread of various Sexually Transmitted
(b) Genital warts
Diseases (STDs).
(ii)
Yes, bacteria are also known to cause STDs.
(ii) Proper medication and checkups will help in the
For example, Syphilis is an STD caused by bacteria,
production of healthy children.
Treponema, pallidum.
(iii) Better sex education and awareness help in maintaining
(iii)
Condoms protect us from acquiring STDs. It also helps
the population and prevent the population explosion.
in avoiding pregnancy.
(iv) Unwanted pregnancies are avoided.
(iv)
IUCD stands for Intra-Uterine Contraceptive Device. It
The reproductive health in India has improved
is used to prevent pregnancy, e.g. Copper-T
tremendously over the past 50 years. The areas in which
(v)
Emergency contraceptives may prevent pregnancy if
reproductive health has improved includes
used within 72 hrs of coitus/intercourse.