When the blood hemoglobin of a normal person and a sickle-cell patient is placed in an electrophoretic field,what will be observed?

Tjio and Levan's contribution is very significant because they

The offspring from a cross between two individuals differing in at least one set of characters is called

Pick out the correct statements.
$I.$ Haemophilia is a sex-linked recessive disease
$II.$ Down's syndrome is due to aneuploidy
$III.$ Phenylketonuria is an autosomal dominant gene disorder
$IV.$ Phenylketonuria is an autosomal recessive gene disorder
$V.$ Sickle cell anaemia is an $X$-linked recessive gene disorder

Choose the correct option regarding genetic disorders and inheritance patterns.

If a starfish possesses six arms instead of five,what is this an example of?