Question

Sickle cell disease is caused by a:

A. change in one allele.

B. change in the size of a chromosome.

C. change in two proteins.

D. change in the number of chromosomes in a cell.

Answer 1

think A.change in one allele.

Answer 2

Yep,
B, C and D would probably cause a lot more problems than just sickle cell anemia.

Sickle cell anaemia is caused by a point mutation in the β-globin chain on chromosome 11.

Answer 3

Yup A is Correcto :)