Question

which of the following is homozygous recessive? ff tt aa rr

Explanation:

Step1: Recall Homozygous Recessive Definition

Homozygous recessive means having two identical recessive alleles. Recessive alleles are usually represented by lowercase letters, and homozygous means the two alleles are the same.

Step2: Analyze Each Option

• \( Ff \): Has one dominant (\( F \)) and one recessive (\( f \)) allele, so it's heterozygous.
• \( TT \): Has two dominant alleles (uppercase), so it's homozygous dominant.
• \( AA \): Has two dominant alleles (uppercase), so it's homozygous dominant.
• \( rr \): Has two identical recessive alleles (lowercase), so it's homozygous recessive.

Answer:

D. rr (assuming the options are labeled A: Ff, B: TT, C: AA, D: rr)