The genes of the seed

Two alleles, $A$ and $a$, are in a female plant and in a male plant. The egg and the two polar nuclei carry the same female allele, and both male gametes carry the same male allele. You will find the genes of the embryo and of the endosperm and count the seeds of a cross.

The idea. The embryo is the female allele plus the male allele. The endosperm is the female allele twice plus the male allele.

Your tasks.

1. Finish embryo. It gives the genotype of the embryo as a word, with the capital letter first.
2. Finish endosperm. It gives the genotype of the endosperm in the same way.
3. Finish share. It gives the share of the seeds of the cross $Aa \times Aa$ that have a given endosperm genotype, as a fraction.