If a parent is heterozygous for a gene, 1/2 of the time they will contribute a dominant allele to their offspring and 1/2 of the time they will contribute a recessive allele to their offspring. the phenotypes of the resulting offspring will be dominant and recessive. a. 1/4; 3/4b. 1/2; 1/2c. all (4/4); no (0/4)d. 3/4; 1/4

Option D

Explanation:

Let us take an example  "T" represents the allele for tall height

"t" represents the allele for short height

and T is dominant over t

If parents are heterozygous i.e "Tt" and a cross is carried out between them , then the following offspring are produced.

Tt * Tt

TT, Tt, Tt, tt

Out of four one will be homozygous dominant (TT) and two will be heterozygous dominant(Tt) offspring. While remaining "tt" would be homozygous recessive.

The phenotypes of the resulting offspring will be ___3/4__ dominant and ___1/4__ recessive.

Hence, option D is correct