An individual who displays the disease sickle-cell anemia must have inherited the deleterious allele from both phenotypically normal parents. what, therefore, is this individual?

I think the individual is therefore homozygous recessive. Sickle cell anemia is a disorder of the blood caused by an inherited abnormal hemoglobin. The abnormal hemoglobin causes distorted red blood cells. The sickle red blood cells are fragile and prone to rupture. Sickle cell anemia is as a result of mutation in a single gene (β-thalassemia). 

The return of the wolf to yellowstone national park will probably affect the bird population to some degree, not significantly. while wolves will hunt birds when necessary, they prefer to hunt larger prey. the bird population will most likely only be affected when hunting is scarce for the wolves. birds of prey will also probably not be affected as much as other birds who spend more time on the ground hunting for food as the tend to spend more time in the air or in trees since they do not need to stay on the ground for long due to the nature of the way they hunt.