The idea of use and disuse of organs was given by

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.

Evolution means

Theory of inheritance of acquired characters was putforth by

Theory of natural selection was given by

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.