2. Draw a Punnett square to find the genotypic and phenotypic ratios of the following situation. People who are able to curl the edge of their tongue upwards possess a dominant allele for the trait. Suppose a man who cannot roll his tongue marries a woman who is heterozygous for tongue rolling. What are the expected genotypic and phenotypic ratios of their offspring? (4 marks)

Step 1 ：Given a man who cannot roll his tongue (genotype rr) and a woman who is heterozygous for tongue rolling (genotype Rr).

Step 2 ：Create a Punnett square to find the genotypic and phenotypic ratios of their offspring.

Step 3 ：Punnett square: [['rR', 'rR'], ['rr', 'rr']]

Step 4 ：The genotypic ratios of their offspring are \(\boxed{50\% Rr}\) and \(\boxed{50\% rr}\).

Step 5 ：The phenotypic ratios are \(\boxed{50\%}\) able to roll their tongue and \(\boxed{50\%}\) unable to roll their tongue.