Solved Examples on Evolution
(1) According to one of the most widely accepted theories the earth’s atmosphere, before any life had originated on this planet, consisted of a mixture of [CPMT 1981, 84, 2002]
(a) Water vapour, H2, NH3 and CH4
(b) H2, CO2, NH3 and CH4
(c) CO2, NH3, CH4 and water vapour
(d) CH4, O2 and water vapour
Answer: a
Solution:
According to one of the most widely accepted theories the earth’s atmosphere, before any life had originated on this planet, consisted of a mixture of Water vapour, H2, NH3 and CH4.
(2) If there was no CO2 in the earth's atmosphere, the temperature of earth's surface would be [CBSE PMT 1998]
(a) Same as present
(b) Less than the present
(c) Higher than the present
(d) Dependent on the amount of oxygen in the atmosphere
Answer: b
Solution:
If there was no CO2 in the earth's atmosphere, the temperature of earth's surface would be less than the present
(3) Which of the following is not atavistic in humans [CPMT 2001]
(a) Tail in some babies
(b) Enlarged canines
(c) Six fingers
(d) Dense body hair
Answer: c
Solution:
Having six fingers is not atavistic in humans.