In recent years,$mt-DNA$ and $Y$-chromosome $DNA$ sequences have been used for the study of human evolution because:

Choose the correct option for the variations suggested by Darwin.

Which technique is used to prove that antibiotic-resistant bacterial mutants are pre-existing and not induced by the environment?

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

Given below are two statements.
Statement-$I$: Elimination of particular alleles from a population due to natural disasters is called genetic drift.
Statement-$II$: Sudden temporary heritable change in the gene is called point mutation.
In the light of above statements,choose the most appropriate answer from the options given below:

State and explain any three factors affecting allele frequency in populations.