Apurple-flowered pea plant is crossed with a white-flowered pea plant. all the f1 plants produced purple flowers. when the f1 plants are allowed to self-pollinate, 401 of the f2s have purple flowers and 131 have white flowers. what are the genotypes of the parental and f1 generation plants?

Parentals: PP (purple) and pp (white)

F1: Pp (purple)

Explanation:

When the two parental plants of differing phenotypes (purple or white flowers) cross, the F1 is 100% purple. This result suggests that the parentals were true breeding (homozygous), with purple flowers being the dominant allele.

When the F1 self pollinates, the F2 shows proportions very similar to 3/4 purple and 1/4 white (401/532 ≅ 3/4 and 131/532 ≅ 1/4). The 3:1 phenotypic ratio is typical of the offspring resulting from a cross between two heterozygous individuals.

The results make sense if the genotypes of the different generations are:

Parentals: PP (purple) X pp (white)

F1:                          Pp (purple)

F2:  1/4 PP, 2/4 Pp, 1/4 pp

after receiving a stimus, the sensory receptors send(s) signals to the appropriate area of the body.  

the must be sensory neurons.  

hope its .

not necessarily. higher fitness requires the organism to be reproductive successful. for example, an organism at age 10 with 15 offspring is much more fit than an organism at age 15 with only 5 offspring.