Can you please explain this to me?

Question

List all the possible genotypes of a pea plant with purple flowers and round seeds.

Answer 1

When you talk of genotype it refers to the alleles of the organism. Like FFpp, FfPp. For example:

Dominant: White Flower (F)
Recessive: Purple Flower (f)

The possible genotypes for white flowers in the F1 generation are: FF and Ff. When for purple flowers is only ff.
So in the exercise you are proposing, you must list all the possibilities in the alleles for obtaining the physical characteristic of the individuals, take into account if the traits you mention are dominant or recessive.