Question 1 - Case Based Questions (MCQ) - Chapter 8 Class 10 - How do Organisms Reproduce?

Read the following passage and answer any four questions from (a) to (e).

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.

(b) What is the result of reckless female foeticide?

(c) Which contraceptive method changes the hormonal balance of the body?

(d) Write two factors that determine the size of a population.

(e) What should be maintained for a healthy society?

(i) rate of birth & death rate

(ii) male & female sex ratio

(iii) child sex ratio

(iv) None of these

Answer:

(a)

Common signs for sexual maturation in boys and girls are:

• Growth of excessive hair on body parts like armpits,face and pubic area.

• Broadening of shoulders and chest in boys and development of breast or mammary glands in girls.

(b)

Female foeticide is the killing of an unborn girl child. The result of reckless female foeticide will be the imbalance of male to female sex ratio.

(c)

Chemical methods of contraception i.e., oral pills change the hormonal balance of the body.

(d)

Factors which determine size of the population are:

• Birth rate - Number of babies born every year per 1000 people in a population.
• Death rate - Number of deaths every year  per 1000 people in a population.

(e)

Checking the options

• (i) rate of birth & death rate - Does not lead to a healthy society.  
• (ii) male & female sex ratio - Leads to a healthy society.
• (iii) child sex ratio - Does not lead to a healthy society.    
• (iv) None of these 

So, the correct answer is (ii).