Question

two plants are heterozygous for seed shape and have round seeds. if the two plants are crossed, what is the probability that the offspring will have wrinkled seeds?
25 percent
50 percent
75 percent
100 percent

Explanation:

Step1: Identify Genotypes

Heterozygous plants have genotype \( Rr \) (round is dominant, wrinkled is recessive, \( R \) = round, \( r \) = wrinkled).

Step2: Set Up Punnett Square

Cross \( Rr \times Rr \). The Punnett square has four cells:

• \( R \times R = RR \)
• \( R \times r = Rr \)
• \( r \times R = Rr \)
• \( r \times r = rr \)

Step3: Determine Phenotypes

• \( RR \), \( Rr \), \( Rr \) show round seeds (dominant).
• \( rr \) shows wrinkled seeds (recessive).

Step4: Calculate Probability

Out of 4 possible genotypes, 1 is \( rr \). So probability is \( \frac{1}{4} = 25\% \).

Answer:

25 percent