In a dihybrid cross in rabbits using W for white fur (dominant) and w for black fur (recessive), and E for long ears (dominant) and e for short ears (recessive), what is the probability of offspring that are black with long ears if both parents are WwEe?

• A. 1/16
• B. 9/16
• C. 3/16
• D. 5/16

Answer: (C)

Dihybrid crosses rely on independent assortment, so the chance of a combined phenotype is the product of the separate probabilities for each trait. For fur color, white is dominant (W) and black is recessive (w); to be black, an offspring must be ww. Crossing Ww with Ww gives WW, Ww, and ww in a 1:2:1 ratio, so the probability of ww (black) is 1/4. For ear length, long ears are dominant (E) and short ears recessive (e); to have long ears, the offspring need E_. Crossing Ee with Ee gives EE, Ee, and ee in a 1:2:1 ratio, so the probability of long ears (E_) is 3/4. Since the two genes assort independently, multiply these probabilities: 1/4 × 3/4 = 3/16. Therefore, the chance of offspring that are black with long ears is 3/16.