In fruit flies straight wings (S) are dominant over curled wings. A homozygous fruit fly is crossed with a heterozygous fruit fly. A Punnett square predicts what percentage of the offspring will be he?

In this cross, all offspring will have straight wings since the homozygous fly can only pass on the dominant allele for straight wings (SS) while the heterozygous fly can pass on either straight (S) or curled wings (s). Therefore, all offspring will inherit one straight wing allele, resulting in them having straight wings.