20. A cross involving a simple dominant and recessive trait, where both parents are heterozygous, what would be the phenotype ratio?
Cross Aa x Aa
Use a Punnet Square
| A | a | |
|---|---|---|
| A | AA - red | Aa - red |
| a | Aa - red | aa - white |
The resulting ratio amongst the four results 3/4 are red 1/4 are white; the ratio is 3:1.