Question

A) The average life span differs very widely for different organisms. While some live for short
periods, others may have a life of several decades or even centuries. None,however, lives
forever. Even if an individual meets with no fatal accident, is not eaten up by a predator, or does
not suffer a killing disease, death still comes as the natural
final result of old age.
B) Aging is defined as the process of progressive deterioration in the structure and function of
the cells, tissues and organs of the organism as it grows older. The area of developmental
biology which is concerned with the study of the processes of aging is
known as gerontology.
C) Why should an animal age at all? Why do some animals age more rapidly and have a shorter
life span than others? Why do different cell types and tissues within the same individual age at
different rates? We still do not know enough about the process and
causes of aging, although many theories have been proposed to explain this phenomenon.
D) Some biologists suggest that adverse changes in the environment are the causes of aging in
the organisms. Others believe that aging is an intrinsic genetic property of the cells of an
organism. According to a compromise theory, aging is due to an interaction between hereditary
factors (genes) and the environment. We know, for
example, that domestication of animals increases their life span. Another theory proposes that
the cells and organisms with a high rate of metabolism age more rapidly and die sooner than
those with a relatively lower rate of metabolic activity.
E) A more recently proposed immunity theory of aging suggests that the decline and
disappearance of the thymus gland by late middle age in man is the primary cause of aging.
With the disappearance of this gland, the defences of the body against foreign invasion
weakens, and, at the same time, the number of defective, abnormal and harmful cells produced
in the body itself goes up. This results in increasing damage and destruction of the tissues.
F) While each theory of aging is supported by some evidence, none of them comprehensively
explains this phenomenon. A theory which explains aging in all kinds of organisms can be
formulated only when more facts are known about aging processes in a variety of species living
under different conditions.
Q1. On the basis of your understanding of the above passage make notes on it using
headings and sub-headings. Use recognizable abbreviations wherever necessary. Give
an appropriate title.
Q2. Write the summary of above passage in about 80 words.

Answer 1

Answer:

B

Explanation:

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