Point mutation may occur due to
Gain of a segment of $DNA$
Deletion of segment of $DNA$
Alternation in $DNA$ sequence
Change in a single base pair of $DNA$
Wilson detected the colour blindness disease in
Animal which remains male initially, then changes to female $(Tapeworm\, proglottides)$ is called
Fraternal twins are produced when
Polytene chromosomes in salivary glands of Drosophila are formed as a result of
Extranuclear inheritance is a consequence of presence of genes in