Question

recessive (3/4)
correct
both parents must donate a blue - eyed allele for a 25% chance of expression in offspring.
incorrect
only one parent needs to donate an allele for full expression.
dominant (4/4)
incorrect
a white chicken and black hen produce offspring with both black and white feathers.
incorrect
this is an allele that requires a homozygous genotype to be expressed.

Explanation:

In genetics, recessive traits require two copies of the recessive allele (one from each parent) for the trait to be expressed in offspring. A 25% chance of expression in offspring occurs when both parents are carriers (heterozygous) and contribute the recessive allele. Dominant traits only need one copy of the dominant allele to be expressed. The statements about the white - black chicken offspring and the allele requiring homozygous genotype for expression are incorrect interpretations. The correct statement about the recessive trait is that both parents must donate the relevant recessive allele for the 25% chance of expression in offspring.

Answer:

The correct statement is "Both parents must donate a blue - eyed allele for a 25% chance of expression in offspring."