Comment on the statement that ''evolution and natural selection are end result or consequence of some other processes but themselves are not processes''.

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.

Contribution of scientist :

$(a)$ Charles Darwin

$(b)$ Lamarck

The scientists believe that evolution is gradual. But extinction, part of evolutionary story, are 'sudden' and 'abrupt' and also group-specific. Comment whether a natural disaster can be the cause for extinction of species.