Answer:
See the attached for the Punnet square
Likelihood of their child having short eye lashes - 50% or 1/2
Step-by-step explanation:
Let the allele for eye lashes be represented by E. Homozygous genotype will be EE (for long eye lashes) or ee (for short eye lashes) while heterozygous genotype will be Ee. Assuming long eye lashes allele E is dominant over shor short eye lashes e:
Heterozygous man marries a short eye lashes woman: Ee x ee
Ee x ee = Ee (long lashes), Ee (long lashes), ee (short lashes) and ee (short lashes.
That is, 50% or 1/2 of the offspring will have long eye lashes while the remaining 50% or 1/2 will have short eye lashes.