Having hair on the back of the hand is dominant (h), and not having the hair is recessive (h). a mother has hh and a father has hh. if they have a child, which genotype will make their child not have hair on the back of his or her hand?

All offsprings which have "hh" genotypes will not have hair on the back of his or her hand

Explanation:

Having hair on the back of the hand is a dominant trait in humans , represented by "H"

Not having hair on the back of the hand is a recessive trait in humans , represented by "h"

When a dominant and recessive trait occur together, only the trait associated with the dominant allele is expressed.

Now  a cross is being carried between two parents having following genotype

Father - "hh"

Mother - "Hh"

The following offsprings are produced as per the punnet square given below -

hh

HHhHh

hhhhh

A recessive trait is expressed when both the cell has both the recessive traits.

Thus, all offsprings which have "hh" genotypes will not have hair on the back of his or her hand