Two zoogeographical regions separated by high mountain ranges are

The closely related,morphologically similar,sympatric populations that are reproductively isolated are designated as

Assertion: From an evolutionary point of view,the human gestation period is believed to be shortening.
Reason: One major evolutionary trend in humans has been the larger head undergoing a relatively faster growth rate in the foetal stage.

Select the mismatched pair.

Match the columns:

Column-$I$	Column-$II$
$(1)$ Mutation	$(a)$ Change in population allele frequencies due to chance alone.
$(2)$ Gene flow	$(b)$ Difference in survival and reproduction.
$(3)$ Natural selection	$(c)$ Immigration,emigration change allele frequencies.
$(4)$ Genetic drift	$(d)$ Source of new alleles.

Choose the correct pair.