Question

1. A heterozygous tall pea plant is crossed with a short plant. The probability that an F1 plant will be tall is (1 point)
25%.
50%.
75%.
100%.

Answer 1

75%

Answer 2

Punnett Squares help with this. The heterozygous plant has two different alleles - one for tallness, the other for shortness. You are told that it is tall so you know that one tall allele is sufficient to confer tallness - that lets you sort out the dominance relationship. Tall is dominant to short.

The short plant, therefore, is homozygous recessive.

Your genotypes are Tt and tt. Doing a Punnett Square will give you the genotypes - which you can interpret as phenotypes - of the offspring. Hope that's helpful.

Answer 3

1. A heterozygous tall pea plant is crossed with a short plant. The probability that an F1 plant will be tall is (1 point)
(0 pts) 25%.
(1 pt) 50%.
(0 pts) 75%.
(0 pts) 100%.
1 /1 point