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

The individual is homozygous recessive.

Explanation:

Sickle cell anaemia is an inherited blood disorder in which there is not much available red blood cells to carry oxygen.

The individual is homozygous recessive because such inherited the two deleterious allele SS.

For an individual to have inherited sickle cell anaemia from the parents, it means the two parents are carriers.

The father have AS gene and the mother have AS gene which is the carrier of sickle cell anaemia gene, the individual inherited the deleterious alleles from the phenotypically normal parents.

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.