Question

a father had one allele for detached earlobes and one allele for attached earlobes. what is the probability that he produces a gamete with th allele for attached earlobes

Answer 1

So a gamete only contains half the chromosome.
Let D = detached earlobes and d = attached earlobes
The father is Dd, so he can produce a gamete that's either D or d. So there is a 50% probability that the father will produce a gamete with the allele for attached earlobes.