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Class 10 SELINA Solutions Biology Chapter 13 - The Reproductive System

The Reproductive System Exercise Ex. 1

Solution A.1

(d) Bulbo-urethral gland

Solution A.2

(d) Menarche

Solution A.3

(d) 14 days

Solution A.4

(a) Fallopian tube  

Solution A.5

(a) Leydig cells 

Solution A.6

(d) Haemoglobin 

Solution A.7

(c) Scrotal sac

Solution A.8

(c) Chorion

Solution A.9

(d) Gestation

Solution A.10

(d) Inguinal canal

Solution B.1

(a) Seminal vesicles, Prostate gland and Bulbo-urethral glands

(b) Oestrogen and Progesterone

(c) Menstrual phase, Follicular phase, Ovulatory phase and Luteal phase

(d) Identical twins and Fraternal twins

(e) Amnion, Chorion and Allantois

Solution B.2

(a) Ovulation  fertilization  implantation  gestation child birth

(b) Sperm  sperm duct  urethra  coitus  vagina  ovum

(c) Testes  Sperms  Sperm duct  Semen  Penis

(d) Menarche Puberty  Reproductive age  Menstruals  Menopause

(e) Graafian follicle  Ostium  Fallopian tube  Uterus

Solution B.3

(a) Menarche

(b) Ovulation

(c) Menstruation

(d) Fertilization

(e) Implantation

Solution B.4

Column I

Column II

(a) Acrosome

(v) spermatozoa

(b) Gestation

(vii) Time taken by a fertilized egg till the delivery of baby

(c) Menopause

(vi) complete stoppage of menstrual cycle

(d) Foetus

(i) An embryo which looks like human baby

(e) Oogenesis

(iii) ovum producing cells

(f) Ovulation

(ii) Luteinizing hormone



Solution B.5

(a) Sperm: Spermatogenesis :: Ovum : Oogenesis

(b) Female gonad: Ovaries :: Male gonad : Testes

(c) Follicle cells : Ova :: Seminiferous tubules : Sperms

(d) Leydig cells : Testosterone :: Corpus luteum : Oestrogen

(e) Follicular phase : 5-12 days :: Luteal phase: 15-28 days

Solution B.6

(a) Uterine tube (Rest are parts of the male reproductive system)

(b) Seminiferous tubule (Rest are accessory glands of the male reproductive system)

(c) Ureter (Rest are parts of the female reproductive system)

(d) Choroid (Rest are extraembryonic membranes of the embryo)

(e) Zona pellucida (Rest are parts of the human sperm)

Solution C.1


(i) False

(ii) False

(iii) False


(i) Fertilization occurs in the fallopian tube.

(ii) Vagina is also known as the birth canal.

(iii) Nutrition and oxygen diffuse from the mother's blood into the foetus's blood through placenta.

Solution C.2



1. Corpus luteum

1. Secretes progesterone & other hormones to prepare the uterine wall for the receival of the embryo

2. Testes

2. Produces male gametes in mass

3. Placental disc

3. Supplies oxygen and nutrients to embryo

4. Oxytocin

4. Increases the force in uterine contractions during child birth

5. Umbilical cord

5. Connects placenta with foetus

6. Fallopian tube

6. The site of fertilization for the sperm and ovum

Solution C.3

(a) Foetus:

It is contained in the uterus.

In foetus, limbs have appeared and resembles the humans unlike the embryo which is a growing or dividing zygote.

(b) Hyaluronidase:


It is an enzyme secreted by the sperm that allows the sperm to penetrate the egg.

(c) Morula:

It is the stage in the development of human embryo which consists of a spherical mass of cells. Blastocyst

(d) Amniotic fluid:

Between amnion and embryo

It protects the embryo from physical damage, keeps the pressure all around embryo and prevents sticking of foetus to amnion.

(e) Placenta:

Placenta is formed by two sets of minute finger like processes called the villi. One set of villi is from the uterine wall and the other set is from the allantois.

Oxygen and amino acids.

Progesterone and oestrogen.

(f) Implantation:


It occurs in about 5-7 days after ovulation.

Solution C.4

(a) Inguinal canal: It allows the descent of testes along with their ducts, blood vessels, nerves, etc.

(b) Testis: It helps in the production and storage of sperms. It also assists in the production of male sex hormone, testosterone.

(c) Ovary: It helps in the production and storage of ova. It also assists in the production of female sex hormones, oestrogen and progesterone.

(d) Oviduct: It is the site for the fertilization of the ovum and the sperm. The zygote travels down into the uterus through the oviduct.

(e) Uterus: It protects and nourishes the growing embryo.

Solution C.5

(a) Seminal vesicle: It is located between the posterior surface of the urinary bladder and the rectum.

(b) Uterus: It is situated in the pelvic cavity between the urinary bladder and the rectum.

(c) Placenta: It is attached to the uterine wall.

(d) Acrosome: It is present at the top of the head of the sperm

(e) Vagina: It begins from the lower end of the uterus (cervix) upto the outside.

Solution D.1

(a) Reproduction: Reproduction is the process of formation of new individuals by sexual or asexual means, which can repeat the process in their own turn.


(b) Hernia: Hernia is an abnormal condition which is caused when the intestine due to the pressure in abdomen bulges into the scrotum through the inguinal canal.


(c) Ovulation: Ovulation is the release of the mature ovum by the rupture of the Graafian follicle.


(d) Puberty: Puberty is the period during which immature reproductive system in boys and girls matures and becomes capable of reproduction.


(e) Fertilisation: The fusion of the male gamete (sperm) and the female gamete (ovum) to form a zygote is called fertilisation.


(f) Hymen: Hymen is a thin membrane which partially covers the opening of the vagina in young females.

Solution D.2

(a) Differences between spermatogenesis and oogenesis:



It is the process of production of sperms in seminiferous tubules of testes.

It is the growth process in which an ovum becomes a mature egg.


(b) Differences between implantation and gestation:



It is the fixing of the blastocyst to the endometrial lining of the uterus or the wall of the endometrium.

It is the time period of development of the embryo in the uterus.


(c) Differences between pregnancy and parturition:



It is the state of carrying a developing embryo or a foetus within the female body.

It is the process of giving birth to the young ones at the end of the gestation period.


(d) Differences between placenta and umbilical cord:


Umbilical cord

It is disc-like structure attached to the uterine wall.

It is a cord containing blood vessels which connects the placenta with the foetus.


(e) Differences between identical and fraternal twins:

Identical twins

Fraternal twins

They are produced from one ovum i.e. one developing zygote splits and grows into two fetuses.

They are produced when two ova get fertilized at a time.


(f) Differences between menarche and menopause:



It is the onset of menstruation in a young female at about the age of 13 years.

It is the permanent stoppage of menstruation in females at about the age of 45 years.


Solution D.3

Testes are responsible for the production of male gametes i.e. sperms. The normal body temperature does not allow the maturation of the sperms. Being suspended outside the body cavity, the temperature  in the scrotal sac is 2 to 3oC which is the suitable temperature for the maturation of the sperms

When it is too hot, the skin of the scrotum loosens so that the testes hang down away from the body. When it is too cold, the skin contracts in a folded manner and draws the testes closer to the body for warmth.

In an abnormal condition, in the embryonic stage, the testes do not descend into the scrotum. It can lead to sterility or incapability to produce sperms.

Solution D.4

Secondary sexual characters in males:

(i) Beard and moustache

(ii) Stronger muscular built

(iii) Deeper voice

Secondary sexual characters in females:

(i) Breasts in females

(ii) Large hips

(iii) High pitched voice

Solution D.5

The accessory reproductive organs include all those structures which help in the transfer and meeting of two kinds of sex cells leading to fertilization and growth and development of egg up to the birth of the baby.

For example: uterus in females, penis in males.

Solution D.6

Primary Reproductive Organs

Accessory Reproductive Organs

The primary reproductive organs produce sex cells.

The accessory reproductive organs help in the transfer and meeting of two kinds of sex cells leading to fertilization.

The primary reproductive organs do not help in the development of baby.

The accessory organs help in the growth and development of egg up to the birth of baby.

Example: Testes in males and ovaries in females.

Example: penis in males, Uterus, vagina in female.

Solution D.7

(a) After fertilization zygote is formed inside the fallopian tube.

(b) The zygote then divides repeatedly to form a spherical mass of cells known as 'Morula'.

(c) The morula then develops into a hollow sphere of cells with a surrounding cellular layer and an inner cell mass projecting from it centrally. This stage is known as the 'blastocyst'. It implants itself into the uterine wall.

(d) From the blastocyst arises an embryo which is around 3 weeks old. It is a tiny organism that hardly resembles human being.

(e) By the end of 5 weeks, the embryo is with a develoed heart and blood vessels.

(f) By the end of 8 weeks, limbs are developed. This stage is known as 'foetus'.

(g) At the end of nearly 40 weeks i.e. end of gestation period, the infant is born.

Solution D.8

Testosterone is the male reproductive hormone produced by the interstitial cells or the Leydig cells. These cells are located in the testes. They serve as a packing tissue between the coils of the seminiferous tubules. Therefore, it can be said that the testes produce the male hormone testosterone.

Solution E.1

(a) Excretory system and Female Reproductive system.








Fallopian Tube








Urinary Bladder








(c) Function of fallopian Tube (part 3): The fallopian tubes carry the ovum released from the ovary to the uterus.


Function of infundibulum (part 4): Infundibulum is the funnel shaped distal end of the ovary which picks up the released ovum and pushes it further on its passage into the fallopian tube.


Function of ovary (part 5): Ovary produces female gametes i.e. ova.


Function of uterus (part 6): Uterus allows the growth and development of the embryo.


(d) If fallopian tube (part 3) on both sides gets blocked, the ovum released by the ovary will not be pushed into the oviduct and hence, there will be no possibility of fertilisation.

Solution E.2

(a) The organ system is human male reproductive system.

(b) 1 - Testis, 2 - Scrotum, 3- Epididymis, 4 - Sperm duct, 5- Seminal vesicle, 6- Bulbo-urethral gland, 7- Urethra

(c) Epididymis (3) stores the sperms for some days during which they mature and become motile.

The secretion of bulbo-urethral gland (6) serves as a lubricant.

(d) Interstitial cells (Leydig cells) of testis produce testosterone.

(e) The testes are located in a separate sac suspended outside the body because, they require a lower temperature for sperm production. A slightly higher temperature does not permit the maturation of the sperms. In the scrotum, the temperature is 2 - 3 degrees lower than the body temperature. This assists in sperm production.

Solution E.3

(a) The organ is testis. Each testis is contained in a thin-walled sac of skin called the scrotum which is located outside the abdominal cavity.

(b) 1 - Epididymis, 2 - Efferent ducts, 3 - Testis, 4 - Sperm duct (Vas deferens)

(c) The mature sperms pass into the efferent duct (2).

Sperm duct (4) helps in transportation of the sperms from the testes upwards to the abdomen.

(d) Testes (3) contains seminiferous tubules (cellular structure) and produces testosterone (hormone).

(e) Seminiferous tubule

Solution E.4



1. (Urinary bladder)

  • Stores urine

2. (Ureter)

  • Carries urine from the urinary bladder to the urethra

3. (Bulbo-urethral glands)

  • Secretion serves as a lubricant 

4. (Sperm duct/Vas deferens)

  • Allows the transit of sperms from the testicles to the outside of the body
  • Allows maturation of sperm cells

5. (Urethra)

  • Carries urine from the bladder to outside of the body
  • Ejaculation of semen when the male reaches orgasm

6. (Testis)

  • Production of sperms

7. (Scrotum)

  • Protects the testes
  • Acts as a climate control system for the testes


8. (Epididymis)

  • Stores and allows the maturation of sperms before release


Fallopian tubes (oviducts) in females are analogous to sperm ducts in males. Sperm ducts carry sperms to the urethra, while fallopian tubes carry ova to the uterus.

Solution E.5

(a) 1 - umbilical cord,

2 - placenta,

3 - amnion,

4 - mouth of uterus,

5 - muscular wall of uterus

(b) Gestation

(c) 280 days

(d) Placenta provides the foetus with oxygen and nutrients. In addition, the placenta also removes carbon dioxide and waste products of the foetus.

(e) Progesterone

Solution E.6

(a) 1 - Vagina, 2 - Ovary, 3 - Fimbriae, 4 - Fallopian tube/oviduct, 5 - Uterus, 6 - Cervix

(b) The normal gestation period in humans is 280 days.

(c) During coitus several hundred million sperm are released inside the vagina near the cervix of the uterus.

(d) Functions of the ovary (2):

 They produce eggs for fertilization.

 They produce the reproductive hormones, oestrogen, and progesterone.

(e) The fixing of developing zygote to the endometrial lining of the uterus is called implantation.

Solution E.7

a. A - ovum

B - sperm


b. Sperms are produced in the testis.

The ovum is produced in the ovary.


c. The reproductive cells unite in the fallopian tubes of the female reproductive system.


d. Ovary - Oestrogen and progesterone

Testis - Testosterone


e. Accessory glands:

 Seminal vesicle - Seminal fluid

 Prostate gland - Alkaline secretion

 Bulbo-urethral gland - Lubricant

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