Question

short pea plants exist in the p₁ and f₂ generations. what happens to the phenotype in the f₁ generation?
○ the allele for short pea plants is absent from the genotypes in the f₁ generation.
○ the allele for short pea plants is masked during the f₁ generation, but it is still present in the genotype.
○ the allele for short pea plants is not passed on to the f₁ generation.
done
p₁
short pea plant ↓ tall pea plant
f₁
all tall pea plants
f₂
3 tall : 1 short

Explanation:

This question is about genetics in pea plants, related to Mendelian inheritance. In the P₁ generation, there are short and tall pea plants. The F₁ generation has all tall plants, but in F₂, short plants reappear (3 tall:1 short). This shows the short allele is recessive. In F₁, the short allele is present in the genotype (as heterozygous) but masked by the dominant tall allele, so the phenotype is tall. The first option is wrong because the short allele is present (seen in F₂). The third option is wrong as the short allele is passed (F₂ has short plants). The second option correctly explains that the short allele is masked in F₁ but present in genotype.

Answer:

The allele for short pea plants is masked during the F₁ generation, but it is still present in the genotype.