Assertion : Human ancestors never used their tails and so the tail expressing gene has disappeared in them.
Reason : Lamarck's theory of evolution is popularly called theory of continuity of germ plasm.

Scientists believe that evolution is gradual. However,extinction,which is a part of the evolutionary story,is often 'sudden' and 'abrupt' and also group-specific. Comment on whether a natural disaster can be the cause of the extinction of species.

Which one of the following is not a living fossil?

Given below are four statements $(A-D)$ each with one or two blanks. Select the option which correctly fills up the blanks in two statements.
Statements:
$(A)$ Wings of butterfly and birds look alike and are the results of $ . . . . . . (i) . . . . . . $ evolution.
$(B)$ Miller showed that $CH_4, H_2, NH_3$ and $ . . . . . . (i) . . . . . . $ when exposed to electric discharge in a flask resulted in formation of $ . . . . . . (ii) . . . . . . $.
$(C)$ Vermiform appendix is a $ . . . . . . (i) . . . . . . $ organ and an $ . . . . . . (ii) . . . . . . $ evidence of evolution.
$(D)$ According to Darwin,evolution took place due to $ . . . . . . (i) . . . . . . $ and $ . . . . . . (ii) . . . . . . $ of the fittest.

The $Jurassic$ period of the $Mesozoic$ era is characterized by:

Cleidoic eggs are an adaptation for which of the following?