Question

How many different phenotypes are possible in the offspring of two parents with genotypes AA and aa, where A is the dominant allele for a trait and a is the recessive allele for the same trait?

Answer 1

You need to figure out the alleles contributed by each parent: random assortment means that either allele can go into the gametes but with these parental genotypes there can only be one outcome because each allele is the same as the other.