Answer: 50% will have short hair
Explanation: The allele for a heterozygous dominant short hair is ( Ss ) and the allele for the homozygous long hair which is the recessive trait is ( ss ).
If we cross these alleles the results will be.
s s
S Ss Ss
s ss ss
The results will have 50% Heterozygous dominant short hair and 50% Homozygous recessive long hair.