Mendel first crossed pure-bred pea plants having round-yellow seeds with pure-bred pea plants having wrinkled-green seeds and found that only round-yellow seeds were produced in the `F_1` generation. When F generation pea plants having round-yellow seeds were cross-bred by self pollination, then peas having round- yellow seeds, round green seeds, wrinkled-yellow seeds and wrinkled-green seeds were produced. Mendel collected a total of 2160 seeds.
Which ‘ratio' as established by Mendel have you made use of in answering the part (a) above?