Reproduction and Population Control : 12th Class Biology Q Ans Lesson 21 – NIOS

Reproduction and Population Control : 12th Class Biology Question Answer Lesson 21 – NIOS

Reproduction and Population Control : 12th Class Biology Question Answer Lesson 21 - NIOS

INTEXT QUESTIONS 21.1

  1. At what age do human males and females attain puberty?
    Ans. Male 13-14 years; Female 11-13 years
  2. Name the tubules present in the human testis.
    Ans. Epididymis
  3. Name the various parts of the following,
    (i) Human male reproductive system
    Testes, epididymis, vas deferens, urethra, penis
    (ii) Human female reproductive system– Ovaries, fallopian tubes, uterus, vagina
  4. Name the three types of accessory glands found in the human male reproductivesystem.
    Ans Seminal vesicles, prostate glands, cowper’s glands
  5. State the functions of the following.
    (a) Seminal vesicles – Stock sperms and provide them nourishment
    (b) Prostate glands – Secretes an alkaline fluid, thin fluid keeps the sperms alive and helpst hem to swim vigorously.
    (c) Cowper glands – Cowper’s glands secrete a white, viscous, alkaline secretion resembling mucous which acts as a lubricant.
    (d) Uterus – Inner lining receives, protects and nourishes embryo; contraction of muscular wall exits baby during birth.
  6. What is a gemmule? Explain its importance in the life of sponges.
    Ans. Gemmule is a reproductive body for asexual reproduction in sponges.
    Gemmules help sponges overome periods of drought and form new
    sponges when favourable conditions arise

  7. State the functions of the following in insects:
    (a) seminal vesicles in male– Seminal vesicles store sperms
    (b) spermatheca in female– receives sperms during copulation
    (c) testes in males– generate sperms
    (d) ovaries in females – produce eggs

INTEXT QUESTIONS 21.2

  1. State the main function of placenta.
    Ans. supplies oxygen and food from maternal blood to foetus and transports Heredity carbon dioxide and excretory waste from foetal blood to the maternal blood.
  2. Define the following terms.
    (i) Implantation – the fixation of morula in the wall of uterus is called implantation
    (ii) Placenta – Association between maternal and foetal tissue for physiological exchange, developing embryo is attached to the uterus by a tissue called placenta.
    (iii) Morula : The zygote begins to divide and form a mass of cells called morula.
    (iv) Amnion – From the first few stages of development, the embryo is enclosed in a sac called amnion.
  3. Name the fluid surrounding the foetus in the uterus.
    Ans. Amniotic fluid
  4. Write the function of:
    (a) Prolactin– Prolactin stimulates synthesis of milk in mammary glands in women soon after delivering a body.
    (b) Oxytocin– Oxytocin stimulates uterine contration for child birth and squeezing of milk in mother for new born infant
  5. The first milk that comes out of the mammary gland of the mother is called
    …………… Why is this first milk important for the child?
    Ans. Colostrum; rich in nutrients, fats and protiens. Provides passive immunity

INTEXT QUESTIONS 21.3

  1. List any four reasons for population explosion in India.
    Ans. (i) Advancement in agriculture (ii) Religous and social customs
    (iii) Illiteracy (iv) Desire for a male child

  2. What is the inter-relationship between population, environment and development?
    …………………………………………………………………………………………………………….
  3. What is the effect of uncontrolled population growth on us and our nation?
    Ans.
  4. How does population growth influence urbanization and environmental degradation?
    Ans. The growth in urban population stresses the urban environment by increasing the number of squatter settlements, and slums with no proper sanitation facilities, thus causing air, water and soil pollution beyond permissible limits.
  5. Relate the indiscriminate increase in population with the standard of living inour country.
    …………………………………….

TERMINAL EXERCISES

  1. Define the following terms.
    (i) Demography (ii) Vasectomy (iii) IUD
  2. Mention if the following statements are True (T) or False (F) and rewrite thewrong statements in the correct form.
    (i) Fertilization occurs in vagina.
    (ii) Oxygen and nutrients diffuse from mother’s blood into foetus’s blood
    through amnion.
    (iii) Testes produce testosterone hormone.
    (iv) Pregnancy in women can be prevented by the method of vasectomy.
    (v) Tubectomy involves the cutting and tying of the vas deferens in male.
  3. Choose the odd one in each of the following.
    (i) ovary; Fallopian tube; ureter; uterus
    (ii) epididymis; urethra; vas deferens; uterus
    (iii) Graafian follicle; corpus luteum; Leydig cell Heredity
    (iv) amnion; corpus luteum; amniotic fluid; umbilical cord
  4. Match the terms of Column I with those of Column II and write down the
    matching pairs.
    Column I Column II
  5. Acrosome (a) Testis
  6. Ovulation (b) Luteinizing hormone
  7. Villi (c) Spermatozoa
  8. Fertilization (d) Progesterone
    (e) Placenta
    (f) Vagina
    (g) Fallopian tube
  9. What is reproduction? List tile organs of the human male reproductive system.
  10. What is placenta? How is the placenta beneficial to the mother and the foetus?
  11. What is the significance of testes being located in scrotal sac outside theabdomen of human males?
  12. Write in a sequence the region through which sperm travels from seminiferoustubules up to the urethral opening in human males.
  13. How can the knowledge of process of reproduction help in reducing populationgrowth? Give reasons.
  14. How does increasing population affect environment?
  15. Name the following.
    (i) The organ in which the foetus develops in a human female.
    (ii) The male gamete in humans.
    (iii) The fluid surrounding the developing embryo.
    (iv) Stage when menstruation and ovulation stops in females.
    (v) The surgical method of contraception in human female.
  16. Differentiate between the following.
    (i) Implantation and pregnancy
    (ii) Graffian follicle and corpus luteum
    (iii) Identical twins and fraternal twins
    (iv) Birth rate and death rate
    (v) Vasectomy and tubectomy
  17. Draw the outline of the cross section of the male reproductive system.
    (i) Label the following parts.
    (a) testis (b) epididymis
    (c) seminal vesicles (d) vas deferens
    (ii) Name the hormone produced by the testis.
    (iii) Why are sperms produced in large numbers?
    (iv) State the function of the seminal vesicles.
  18. Write a note on:
    (i) Lactation in humans
    (ii) Gemmule (iii) Cockroah ovaries

NIOS 12th class biology Q Ans

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Himanshu Kumar

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