When members of a population attain sexual maturity at different times preventing inter-breeding,it is termed as . . . . . . isolation.

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

Which one of the following phenomena supports Darwin's concept of natural selection in organic evolution?

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

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

Following are sex ratios obtained from a given area. Which one will show an evolutionary stable strategy between males and females respectively?