AP BIOLOGY

Detailed explanation-1: -For example, if one parent is homozygous dominant (WW) and the other is homozygous recessive (ww), then all their offspring will be heterozygous (Ww) and possess a widow’s peak.

Detailed explanation-2: -In a test cross, the dominant-expressing organism is crossed with an organism that is homozygous recessive for the same characteristic. If the dominant-expressing organism is a homozygote, then all F1 offspring will be heterozygotes expressing the dominant trait (Figure 8.8).

Detailed explanation-3: -A monohybrid cross between a parent that is homozygous dominant and a parent that is homozygous recessive for a particular trait produces offspring that are all heterozygous for that trait. These individuals have two different alleles for that trait.

Detailed explanation-4: -To calculate the probability, count the number of homozygous recessive offspring and multiply to 0.25 (the probability of each allele combination in gametes). With this, the probability of obtaining a homozygous recessive offspring is 0.25.