Which of the following major ideas were proved by Gregor Mendel?

A.

There is a tendency among organisms `to increase rapidly in number if conditions are favourable

B.

There is a struggle for existence among a very large number of offspring

C.

Nature selects organisms which will survive to produce their kind

D.

All species exhibit structural and functional variations

E.

Characteristics of an organism are controlled by genes occurring in pairs

Correct answer is E

No explanation has been provided for this answer.