Explain the following:
$(a)$ Speciation
$(b)$ Natural Selection

(N/A) Speciation:
It is the process of evolution of a new species from pre-existing species.
It occurs due to the accumulation of variations over many generations.
It is driven by processes like genetic drift or geographical barriers such as mountains,rivers,etc.,which lead to reproductive isolation,making the populations incapable of interbreeding.
$(b)$ Natural Selection:
It refers to the change in the frequency of certain genes in a population over time.
It provides a survival advantage to individuals possessing beneficial traits,preventing their elimination from the population.
For example,in a population of beetles,a new variation (green colour) provides a survival advantage to green beetles against predators,whereas the other variant (red) is more easily spotted and perishes.