Question

Which term describes a type of trait that is usually expressed only when an organism has 2 identical alleles for the trait?
A. heterozygous <<<<
B. dominant
C. homozygous <<<<
D. recessive
im stuck between these 2.

Answer 1

The right type of trait is D. recessive.

The terms recessive and dominant are traits (or characters) that relate to alleles.

Homozygosity and heterozygosity characterize individuals. But in the question we are looking for a type of trait (so the answer should not be either of these two).

An allele is dominant if present on only one of the two homologous chromosomes (one of paternal origin, the other of maternal origin), it is capable of expressing a character. Thus it expresses its character that it is present on the two chromosomes of the pair or on only one. An allele is recessive if its expression requires its presence on both homologous chromosomes (in the homozygous state). A dominant allele masks the presence of a recessive allele (in the heterozygous or homozygous state).

Answer 2

The answer is homozygous. I say this because the definition of homo means "same". An example of this is the word homosexual, someone who is homosexual likes the same sex while someone who is heterosexual likes the opposite sex. The actual definition of homozygous is:

"Homozygous is a word that refers to a particular gene that has identical alleles on both homologous chromosomes. It is referred to by two capital letters (XX) for a dominant trait, and two lowercase letters (xx) for a recessive trait."