In humans, if gene B gives brown eyes and gene b gives blue eyes. What will be the colour of eyes of the persons having the following combination of genes?
(a) Bb    (b) bb   (c) BB

In humans, gene B responsible for brown eyes is dominant over the gene b responsible for blue eyes.

Thus,

(a) Bb: will express brown eyes.

(b) bb: will express blue eyes (because recessive gene, b, expresses itself only in the absence of dominant, B, gene).

(c) BB: will express brown eyes.