Mendel's experimental material was

Mendel observed that all $F_1$ progeny plants:

The genotype of vestigial wings in $Drosophila$ is . . . . . . .

Dominance is a phenomenon in which.......

What is the probability of a couple having four sons?

Pure tall plants are crossed with pure dwarf plants. In the $F_1$ generation,all plants were tall. These tall plants of the $F_1$ generation were selfed,and the ratio of tall to dwarf plants obtained was $3:1$. This is called: