Question

question 9.
in a simple monohybrid punnett square, which of these statements are true when crossing two heterozygous parents for any given trait?
choose two correct answers.
a. both parents show the recessive phenotype.
b. 25% of the offspring show the recessive phenotype.
c. 50% of the offspring are heterozygous.
d. all of the offspring will show the recessive phenotype.
e. none of the offspring will show the recessive phenotype.

Explanation:

When crossing two heterozygous parents (genotype $Aa \times Aa$), a Punnett square shows the offspring genotypes are $AA$, $Aa$, $Aa$, $aa$.

• Heterozygous parents ($Aa$) show the dominant phenotype, so A is false.
• The recessive phenotype (from $aa$) is $\frac{1}{4} = 25\%$ of offspring, so B is true.
• Heterozygous offspring ($Aa$) are $\frac{2}{4} = 50\%$ of offspring, so C is true.
• D and E are false as 25% of offspring show the recessive phenotype.

Answer:

B. 25% of the offspring show the recessive phenotype.
C. 50% of the offspring are heterozygous.