Given three possible phenotypes for parents showing dominance (aa, aa, aa), which combination would produce a 1: 2: 1 ratio of genotypes and a 3: 1 ratio of phenotypes? i. aa x aa ii. aa x aa iii. heterozygous x heterozygous iv. aa x aa v. homozygous dominant x heterozygous

The correct answer is-

III. Heterozygous x Heterozygous  and

IV. Aa x Aa.

Genotypic ratio corresponds to the ratio of different genotype produced for the trait ( that depicts the genetic makeup with respect to the trait). On the other hand, phenotypic ratio corresponds to the ratio of phenotypes ( such as tall and dwarf in case of height of pea plant) produced in a generation.

Dominant trait ( depicted by allele with capital letter, such as AA and Aa) masks the expression of recessive trait ( depicted by small letter, such as aa)

Aa and Aa represents heterozygous dominant genotype, which will produce three different genotypes and two different phenotypes in the ratio 1:2:1 and 3:1 respectively.

Refer punnett square.

each of the 46 original chromosomes splits into two daughter chromosomes, so there are two sets of 46 daughter chromosomes that end up in each cell. human cells have 46 chromosomes. each chromosome consists of a pair of identical chromatids attached together by a structure called a centromere.

answer; the correct answer is desert plants;