Mutations are

$A$ sudden large change in a population is known as.......

Mutation introduces new genes into a species and brings about the changes in

$A$ mutation that arises due to a change in a single base pair of $DNA$ is known as .... mutation.

The rate of appearance of new forms is linked to which of the following?

The defect sickle-cell anaemia is caused by the . . . . . . of glutamic acid by valine at the $6^{th}$ position of the . . . . . . globin chain of the haemoglobin molecule.