AP BIOLOGY

Detailed explanation-1: -The correct option is B. Heterozygous. If an organism has two copies of the same allele, for example AA or aa, it is homozygous for that trait. If the organism has one copy of two different alleles, for example Aa, it is heterozygous.

Detailed explanation-2: -A heterozygous individual has two different alleles. Therefore it would have the genotype Aa. An individual with the genotype Aa can make two types of gametes: A and a. Since this is a random process, the individual will, on average, make equal numbers of each gamete. (Frequency of 1/2 for each gamete).

Detailed explanation-3: -Individuals with genotypes AA and aa are homozygotes (i.e., they have two copies of the same allele). Individuals with genotype Aa are heterozygotes (i.e., they have two different alleles at the A locus).

Detailed explanation-4: -Answer and Explanation: In a cross Aa x Aa, this indicates that each parent is heterozygous. This means there is one dominant allele and one recessive.

Detailed explanation-5: -Offspring whose genotype is either AA or Aa will have the dominant trait expressed phenotypically, while aa individuals express the recessive trait.