Im going to explain Mendels 2nd experiment today kids. First of all this experiment was known as a dihybrid instead of a monohybrid like his first one! Take a look at this presentation i've put together to explain it better.
Mendel's second experiment used two different types of phenotypes. The phenotype are determined by the genotype of the pea. Mendel crossed two homozygous peas to get two offspring that were then heterozygous. The thing that determines whether it is herterozygous or homozygous is whats known as alles. His results were a yellow circular pea. Sense the offspring were all alike then that means yellow and circular are the dominant traits. The recessive traits were the ones that disappeared.