Answer:
Incomplete dorminance.
Step-by-step explanation:
Incomplete dorminance occurs when two heterozygous alleles are expressed together which is as a result of dorminant alleles not completely masking the recessive alleles and the two alleles blend together and are expressed phenotypically.
The above question is incomplete dorminance because the allele for tallness in the sheep does not completely mask the allele for shortness and these two alleles blend together to produce intermediate progeny that are expressed phenotypically.