In humans, a dimple in the chin is a dominant characteristic.

1. A man who does not have a chin dimple has children with a woman with a chin dimple whose mother lacked the dimple. What proportion of their children would be expected to have a chin dimple?
2. A man with a chin dimple and a woman who lacks the dimple produce a child who lacks a dimple. What is the man's genotype?
3. A man with a chin dimple and a non dimpled woman produce eight children, all having the chin dimple. Can you be certain of the man's genotype? Why or why not? What genotype is more likely, and why?