Question

To assess Mendel’s law of segregation using tomatoes, a true-breeding tall variety (SS) is crossed with a true-breeding short variety (ss). The heterozygous F1 tall plants (Ss) were crossed to produce two sets of F2 data, as follows:

Answer 1

All you need to do is make a Punnett Square,
where both parents have the genotype (S s).

Answer 2

it is simple....if F1 is selfed u get 1 SS ,1 ss and 2 Ss..the ratio is 1:2:1..this is the genotypic ratio and 3:1 is the phenotypic ratio(tall:short)