A progeny of `F_1`, is crossed with the homozygous recessive parent, What is this cross called? Work out how is it useful?

What is the cross between the progeny of F_1 and homozygous recessive parent called? How is it useful?

Two genes 'A' and 'B' are linked. In a dihybrid cross involving these two genes, the F_1 heterozygote is crossed with homozygous recessive parental type (aa bb). What would be the ratio of offspring in the next generation?

heterozygous tall is crossed with recessive parent what will be the percentage homozygous recessive?

What is a solar cell ? How does it work ? Write its one use.

If a true breeding homozygous pea plant with green pod and axial flower as dominant characters is crossed with a recessive homozygous pea plant with yellow seeds and terminal flowers, then what would be the: genotypes of the two parents phenotypes and genotype of the F_1 offspring phenotypic distribution ratio in F_2 population?