Answer question numbers 3(a) to 3(d) on the basis of your understanding of the following paragraph and the related studied concepts.
The growing size of the human population is a cause of concern for all people. The rate of birth and death in a given population will determine its size. Reproduction is the process by which organisms increase their population. The process of sexual maturation for reproduction is gradual and takes place while general body growth is still going on. Some degree of sexual maturation does not necessarily mean that the mind or body is ready for sexual acts or for having and bringing up children. Various contraceptive devices are being used by human beings to control the size of population.
(a) List two common signs of sexual maturation in boys and girls. (1 mark)
(b) What is the result of reckless female foeticide? (1 mark)
(c) Which contraceptive method changes the hormonal balance of the body? (1 mark)
(d) Write two factors that determine the size of a population. (1 mark)
Answer question numbers 3(a) to 3(d) on the basis of your understanding of the following paragraph and the related studied concepts.
The growing size of the human population is a cause of concern for all people. The rate of birth and death in a given population will determine its size. Reproduction is the process by which organisms increase their population. The process of sexual maturation for reproduction is gradual and takes place while general body growth is still going on. Some degree of sexual maturation does not necessarily mean that the mind or body is ready for sexual acts or for having and bringing up children. Various contraceptive devices are being used by human beings to control the size of population.
(a) List two common signs of sexual maturation in boys and girls. (1 mark)
(b) What is the result of reckless female foeticide? (1 mark)
(c) Which contraceptive method changes the hormonal balance of the body? (1 mark)
(d) Write two factors that determine the size of a population. (1 mark)
(a) Two common signs of sexual maturation in both boys and girls are:
- Hair Growth: Appearance of thick hair in new parts of the body such as armpits and the genital area between the thighs.
- Skin Changes: The skin becomes oily, which often leads to the development of pimples.
(b) Reckless female foeticide leads to a highly skewed child sex ratio (an alarming decline in the female-to-male ratio in the population), which severely disrupts social stability and balance.
(c) Chemical methods (such as oral contraceptive pills) change the hormonal balance of the body so that eggs are not released and fertilisation cannot occur.
(d) The two factors that determine the size of a population (as mentioned in the text) are:
- Birth rate (the rate of births in a given population)
- Death rate (the rate of deaths in a given population)
Marking Scheme
- 1Award 1 mark for listing any two common signs of sexual maturation in boys and girls (0.5 mark each).
- 2Award 1 mark for stating that female foeticide leads to a skewed/imbalanced sex ratio.
- 3Award 1 mark for identifying chemical methods / oral contraceptive pills.
- 4Award 1 mark for listing birth rate and death rate as the two factors (0.5 mark each).
Hint
Focus on common pubertal changes, consequences of gender imbalance, hormonal contraceptives, and population determinants.
Quick Oral Answer
Oral contraceptive pills contain hormones that prevent ovulation. Female foeticide leads to an imbalanced sex ratio. The two main factors determining population size are birth rate and death rate.
Analysis & Explanation
This case-based question tests the understanding of human reproductive health, puberty, and population control.
- Puberty/Sexual Maturation: During adolescence, several hormonal changes occur. Common changes in both genders include hair growth in armpits/pubic regions and increased activity of sebaceous (oil) glands leading to pimples. Gender-specific changes also occur (e.g., breast development in girls, facial hair and voice cracking in boys).
- Female Foeticide: The illegal practice of sex-selective abortion of female fetuses has led to an unnatural imbalance in the male-to-female ratio in many societies.
- Contraception: Hormonal contraceptives (pills) alter the levels of estrogen and progesterone to prevent ovulation. Other methods include barrier methods (condoms), chemical/IUCDs (Copper-T), and surgical methods (vasectomy/tubectomy).
- Population Size: As stated in the passage, the balance between birth rate and death rate determines whether a population grows, declines, or remains stable.
Common Mistakes
- 1Confusing gender-specific signs (like breast development or facial hair) with signs common to both boys and girls.
- 2Not mentioning the impact on the sex ratio specifically when discussing female foeticide.
Interesting Facts
The child sex ratio in some districts of India had fallen below 850 females per 1000 males due to female foeticide, prompting strict laws like the PCPNDT Act to ban prenatal sex determination.
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Frequently Asked Questions
How many marks does this question carry in CBSE Class 10 Science 2020?
This question carries 4 marks in the CBSE Class 10 Science 2020 examination.
Which chapter does this question come from in Science?
This question is from the chapter "How do Organisms Reproduce?" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Human Reproduction and Population Control" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2020 paper?
This question appears in Section A in the CBSE Class 10 Science 2020 paper.