Question

1. in pea plants, yellow seeds are dominant to green seeds. a heterozygous yellow - seeded pea plant (yy) is crossed with a plant that has green seeds (yy).

Explanation:

Step1: Count the number of each genotype

There are 4 boxes in the Punnett square. The number of YY is 0, the number of Yy is 2, and the number of yy is 2.

Step2: Calculate genotype probabilities

The probability of YY is $\frac{0}{4}\times100\% = 0\%$.
The probability of Yy is $\frac{2}{4}\times100\% = 50\%$.
The probability of yy is $\frac{2}{4}\times100\% = 50\%$.

Step3: Determine phenotype probabilities

Since Y (yellow) is dominant, plants with Yy (heterozygous) show the yellow - seed phenotype. Plants with yy show the green - seed phenotype.
The number of plants with yellow seeds (Yy) is 2, and the number of plants with green seeds (yy) is 2.
The probability of yellow seeds is $\frac{2}{4}\times100\% = 50\%$.
The probability of green seeds is $\frac{2}{4}\times100\% = 50\%$.

Answer:

Genotype Probability (\%):
YY: 0
Yy: 50
yy: 50
Phenotype Probability (\%):
Yellow Seeds: 50
Green Seeds: 50