The appearance of a recessive trait in offspring of animals most probably indicates that (1) both parents carried at least one recessive gene for that trait (2) one parent was homozygous dominant and the other parent was homozygous recessive for that trait (3) neither parent carried a recessive gene for that trait (4) one parent was homozygous dominant and the other parent was hybrid for that trait.

If a homozygous tall pea plant and a homozygous short pea plant are crossed,

(a) the recessive trait seems to disappear.
(b) the offspring are of medium height.
(c) no hybrids are produced.
(d) all the offspring are short.

What is the probability that parents heterozygous for a trait will have homozygous offspring?

In a population of organisms. the frequency of the homozygous recessive genotype is $0.3$, the frequency of the heterozygous genotype is $0.6$, and the frequency of the homozygous dominant genotype is 0.1. Fill in the correct numbers for each variable below:
$p^2=$
$2 p q=$\

$$q^2=$$

In Drosophila subobscura, the presence of a recessive gene called grandchildless $(\mathrm{gs})$ causes the offspring of homozygous females, but not those of homozygous males, to be sterile. Can you offer an explanation as to why females and not males are affected by the mutant gene?

Fill in the missing information about the variables involved inth e Hardy-Weinberg equation.

A pair of genes with characteristics that are alike is said to be
a. heterozygous.
b. homozygous.
c. genotype.
d. recessive.

Which statement describes how two organisms may show the same trait yet have different genotypes for that phenotype? [1] One is homocygous dominant and the other is heterocygous. (2) Both are heterozygous for the dominant trait. (3) One is homozygous dominant and the other is homozygous recessive. (4) Both are homozygous for the dominant trait.

Determine whether the rabbits in item $3$ are heterozygous or homozygous.

Choose the best answer.

Assuming a Hardy-Weinberg equilibrium, $21$% of a population is homozygous dominant, $50$% is heterozygous, and $29$% is homozygous recessive. What percentage of the next generation is predicted to be homozyqous recessive?

a. $21$%

b. $50$%

c. $29$%

d. $42$%

e. $58$%

Compare heterozygous genotype and homozygous genotype.

$$\textbf {\color{#19804f}{Calculate}}\text{ the probability that an individual heterozygous for a cleft chin ( Cc) and an individual homozygous for a cleft chin ( cc) will produce offspring that are homozygous recessive for a cleft chin (cc). }$$

In Drosophila, the autosomal genes cinnabar (cn) and brown (bw) control the production of brown and red eye pigments, respectively. Flies homozygous for cinnabar mutations have bright red eyes, fl ies homozygous for brown mutations have brown eyes, and fl ies homozygous for mutations in both of these genes have white eyes. A male homozygous for mutations in the cn and bw genes has bright red eyes because a small duplication that carries the wild-type allele of bw (bw$^{+}$) is attached to the Y chromosome. If this male is mated to a karyotypically normal female that is homozygous for the cn and bw mutations, what types of progeny will be produced?

How are the concepts of dominant, recessive, heterozygous, and homozygous related to the Hardy-Weinberg equation?