Question

In a certain species of parrot, having yellow feathers is a dominant trait and having green feathers is a recessive trait. A homozygous yellow parrot is crossed with a homozygous green parrot. If the female parrot lays four fertile eggs, what will be the phenotypes of the offspring?

Answer 1

If we label the yellow parrot alleles with YY (a homozygote) and green parrot gg (also a homozygote) we can cross these two individuals and determine their future offspring.
YY x gg
Yg Yg Yg Yg
All of the offspring would receive one dominant Y allele from the yellow parent and one recessive allele from the green parent and their genotypes would all be Yg (heterozygotes). Since Y allele is dominant, all of the offspring would have yellow feathers.