In humans, the ability to roll the tongue is a dominant trait; the inability to roll the tongue is a recessive trait. If an individual has two dominant alleles for this trait has a child with an individual who cannot roll his tongue, what is the chance that the child will have one of each allele (heterozygous)? 75% 0% 50% 25% 100%

So since rolling the tongue is a dominant trait it’ll be represented with a capital letter (T) and not being be able to roll the tongue is recessive, so it’ll be a lowercase (t).

If someone with two dominant alleles (TT) has a child with someone who can’t roll their tongue (tt) then there’s a 100% chance the child will be heterozygous.

The Punnet square:

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