When either trait in a dihybrid cross is homozygous recessive, what is that gene?

pleiotropic

epistatic

completely dominant

none of the above

none of the above

Explanation:

The dihybrid organism is an organism that has dominant and recessive alleles for a single trait (Aa), whereas recessive homozygous organisms are those that only have recessive alleles for a trait (aa). If these two organisms participated in a cross between them, the offspring would probably have the alleles Aa, Aa, aa, aa. With this we can not say that any trait of this crossing would have complete dominance, because there is a probability that it will not happen, since 50% of the offspring may have recessive homozygous alleles.

Nor can we claim that an epistatic gene will occur, since epistasis occurs when one gene inhibits the action of another, which may or may not be on the same chromosome. Therefore, it occurs when one gene masks the action of another.

Similarly we cannot affirm the presence of a pleiotropic gene, because pleiotropy is a genetic phenomenon in which a single gene has control over the manifestations of various characteristics.

it would lead to upper respiratory infections and pneumonia.