The most likely reason for the development of resistance against pesticides in insects damaging a crop is

Who proposed the idea of mutations based on his work on plants?

Natural selection can lead to . . . . . . .
$(a)$ stabilisation
$(b)$ genetic drift
$(c)$ directional change
$(d)$ disruption
Choose the correct answer from the options given below:
$(A)$ $(a)$, $(b)$ and $(c)$ only
$(B)$ $(a)$, $(c)$ and $(d)$ only
$(C)$ $(a)$, $(b)$, $(c)$ and $(d)$
$(D)$ $(a)$ and $(c)$ only

In a population of plants,some were extremely tall,and the remaining were extremely dwarf. No plants of the population showed intermediate height. The type of operation of natural selection in the above case is

The Natural Selection Theory of Darwin is objected to,because it:

The essence of Darwinian theory about evolution is $.....$ .