In humans, to fold the tongue is a dominant trait (L), and the straight tongue is the recessive trait. What are the probabilities that the offspring can fold the tongue?

The given question is incomplete as the genotype of the parents is not given, so the answer is providing in the followings case:

1. dominant parent and recessive parent

2. heterozygous parents

1. dominant parent and recessive parent:

dominant parents can be represented by LL and recessive parent is represented by ll, so the gametes would be L, L and l, l.

so,

 L    L

l  Ll   Ll

l  Ll   Ll

so there are all offspring in heterozygous condition as we known one or two dominant allele masks the recessive allele for the trait so 100% offspring can fold their tongue.

2. heterozygous parents

In this case, parents have Ll genotype and gametes would be L and l for each parent so,

    L    l

L   LL  Ll

l    Ll    ll

In this case, one is pure dominant and two heterozygous whereas only one is recessive so, the phenotype of offspring that cant fol the tongue would be:

3/4 = 75%

c) 50% there are four chromosomes. after crossing over, 2 of the four have been changed. that means any gamete has a 2 in 4 chance or 50% chance of receiving the mutated chromosome.