Question

The second generation phenotypes resulting from the cross of true-breeding monohybrid pollination will display a ratio of _____.

4:1
1:2:1
3:1
none of the above

Answer 1

It is 3:1 ..........

Answer 2

The answer is 3:1.

A - the dominant allele
a - the recessive allele

The parental generation (P) is AA and aa:
P AA x aa
F1 Aa Aa Aa Aa

F1 is the first generation of offspring. After their cross, we get the second generation of offspring:
F1 Aa x Aa
F2 AA Aa Aa aa

So we have 3 dominant phenotypes (AA, Aa, and Aa) and 1 recessive phenotype (aa). The ratio is 3:1