a type of bean plant, the trait for yellow pods (B) is dominant to the trait for green pods (b). A plant that is heterozygous for yellow pods is crossed with a plant that has green pods. An incomplete Punnett square of the cross is shown.

Question

(bb)
b b
B
(Bb) b
Which statement correctly describes the probability that offspring of this cross will display certain traits?
A. 75% yellow pods and 25% green pods
B. 50% yellow pods and 50% green pods
C. 100% yellow pods
D.
100% green pods

Answer 1

To determine the probability of the traits of the offspring from the cross between a heterozygous plant for yellow pods (Bb) and a plant with green pods (bb), we can use a Punnett square.

The possible gametes from each parent are:

• Parent 1 (heterozygous): B and b
• Parent 2 (homozygous recessive): b and b

Setting up the Punnett square:

          b         b
       ----------------
    B |     Bb      Bb  |
       ----------------
    b |     bb      bb  |
       ----------------

From the Punnett square:

• 2 out of 4 (or 50%) of the offspring will be Bb (yellow pods)
• 2 out of 4 (or 50%) of the offspring will be bb (green pods)

Thus, the probability of the offspring displaying the traits is:

• 50% yellow pods (Bb)
• 50% green pods (bb)

So, the correct answer is: B. 50% yellow pods and 50% green pods.