Humans have a gene, T, that is involved in muscle formation of the tongue. Individuals homozygous for one allele can roll their tongues, while individuals homozygous for the other allele cannot. If both parents can roll their tongues, but their child cannot, what can be said about the mode of inheritance?

Autosomal Recessive mode of inheritance

Explanation:

If both parents can roll their tongue and their child cannot, it means they are both heterozygote for the trait and since this trait skipped a generation, it can be said to be an autosomal recessive mode of inheritance and not an autosomal dominant mode of inheritance as the later does not skip generations.

google my dude. if it doesn't show up ask me.