Tomas is studying his family's genealogy for an anthropology class. He interviews an uncle about the family's health history and learns that a number of family members have sickle cell anemia. It is safe to assume that:

A. Tomas' family is of Asian descent.
B. Tomas' family members with sickle cell anemia have a defect in the structure of the protein chains of hemoglobin.
C. Tomas' family historically has consumed a low-protein diet.
D. All of these are true

Sickle cell anemia is a medical condition and it is a genetic disorder. The sickle cell anemia is caused by the HBB gene. The mutation in the gene results in the changes in the amino acid sequence responsible for building up of the beta chain of the hemoglobin.

The hemoglobin proteins stick to each other and form stiff fibers. These fibers destroy the shape of the biconcave disc shape of the red blood cells and the cells appear sickle-shaped.

The disorder results in anemia as the blood cells become fragile and they break apart, frequent infections, delayed growth and puberty and problem in vision are common symptoms in this disorder.

According to the above description, B. is the correct option. This is due to the fact that in the Tomas family many members were affected by the disorder. This could have occurred because of the defect of the gene responsible for the production of protein chains of the hemoglobin. The disorder is genetic thus it is expected to inherited by many generations.