When Mendel crossed true-breeding tall pea plants with true-breeding short pea plants, all the offspring were tall. Then he allowed the first generation tall plants to self-pollinate. What were the ratios of phenotypes he expected in the F2 generation?

3:1

Explanation:

Let the allele for tall plant be T;     &

The allele for short plant be t

When Mendel crossed true-breeding tall pea plants(i.e TT) with true-breeding short pea plants(I.e tt); all the offspring were tall.

TT  ×  tt

                     T                    T

t                    Tt                    Tt

t                   Tt                     Tt

we can deduce from the punnet square that the F1 offspring are all heterozygous tall plant.

Now, if the first generation (F1) tall plants are allowed to self-pollinate; we have a cross between Tt and Tt

TT  ×  tt

                     T                    t

T                    TT                    Tt

t                     Tt                     tt

We can see phenotypically that we have 3 tall plant(TT,Tt, Tt) and 1 short plant(tt).

Therefore the ratio of phenotypes he expected in the F2 generation is (3:1)

A.Because this is a monohybrid cross of pea plants that carry two alleles for plant height, the expected ratio is 3 tall : 1 short.

Explanation:

Hope this helps :)

•there must be variation for the particular trait within a population.

•the variation must be inheritable (that is, it must be capable of being passed on from the parents to their offspring).

•individuals with one version of the trait must produce more offspring than those with a different version of the trait.good

explanation:

your body is trying to warm itself up. or more precisely, sensors in your skin send messages to your brain to generate heat to your body.