The number of hydrogen atoms in 6NH3 is .

Hydrogen ⇒ 18

Nitrogen ⇒ 6

Incomplete dominance

Explanation:

Incomplete dominance describes the force behind the emergence of an heterozygous phenotype (gray-coloured butterflies) as offspring of two contrasting homozygous phenotypes (white-coloured and black-coloured parent butterflies)

Furthermore, incomplete dominance set in when neither of the parent traits is dominant over the other.

Thus, gray-colour appear as an intermediate of the white-colour and black-colour