Question

which statement is true of carriers? select all that apply.
a) they can pass a gene for a recessive disorder.
b) they have one dominant allele.
c) they express the recessive trait.
d) they are heterozygous for a recessive disorder.

Explanation:

• Option A: Carriers (for recessive disorders) have the recessive allele and can pass it on. So this is true.
• Option B: For a recessive disorder carrier, they are heterozygous (e.g., Aa), so they have one dominant (A) and one recessive (a) allele. This is true.
• Option C: Carriers do not express the recessive trait (since the dominant allele masks it). So this is false.
• Option D: Carriers are heterozygous (having one dominant and one recessive allele) for a recessive disorder, meaning they have the recessive allele but don't show the disorder. This is true.

Answer:

A) They can pass a gene for a recessive disorder.
B) They have one dominant allele.
D) They are heterozygous for a recessive disorder.