You are a genetic counselor, and a married couple comes to you for advice. The man's father suffers from sickle cell anemia. No one in the family history of the woman has ever had the disease. What would you tell this couple about the probability that their children will have the disease? What would you tell them about the probability that their children will be carriers of the disease?

If you do have sickle cell trait, it doesn't mean your kids will have sickle cell disease. Your child would have to inherit two sickle cell genes to have sickle cell disease. So if your child's mother does not have the sickle cell gene, your child can't get sickle cell disease. But if your child's father has the sickle cell gene, your child can get sickle cell disease.

Explanation:

he forelimbs below belong to four species that descended in a direct line from the ancestral mammal shown above. of the four descendants shown, which species most likely appeared earliest in evolutionary history?