Question

a cross was performed, and the offspring shown to the right were produced. what is the most likely genotype for the parents?
○ bbee × bbee
○ bbee × bbee
○ bbee × bbee
○ bbee × bbee
done
10 mice with black fur, black eyes
2 mice with black fur, red eyes
3 mice with white fur, black eyes
1 mouse with white fur, red eyes

Explanation:

1. First, analyze fur color: Offspring have black (10 + 2 = 12) and white (3 + 1 = 4) fur. The ratio ~3:1 (12:4) suggests a monohybrid cross for fur color, consistent with parents being heterozygous (Bb × Bb), as Bb × Bb gives 3/4 dominant (black) and 1/4 recessive (white).
2. Next, analyze eye color: Offspring have black (10 + 3 = 13) and red (2 + 1 = 3) eyes. The ratio ~4:1 (or ~3:1 when rounded) also suggests a monohybrid cross for eye color, consistent with parents being heterozygous (Ee × Ee), as Ee × Ee gives 3/4 dominant (black) and 1/4 recessive (red).
3. Only the cross BbEe × BbEe involves both traits being heterozygous (dihybrid cross), which matches the observed phenotypic ratios for both fur and eye color in the offspring. Other options (e.g., Bbee × bbEE, BbEE × Bbee, BBEE × bbee) do not produce the 3:1 ratios for both traits seen here.

Answer:

C. BbEe × BbEe