Answer: The type of mutation that causes sickle cell anemia is a substitution mutation.
Step-by-step explanation: A substitution mutation is a type of point mutation that occurs when one nucleotide base pair is replaced by another. In sickle cell anemia, the substitution mutation occurs in the HBB gene, which codes for the beta-globin subunit of hemoglobin. The normal HBB gene has the sequence CTC, which codes for the amino acid glutamic acid. In sickle cell anemia, this sequence is changed to CAC, which codes for the amino acid valine. This change in amino acid sequence causes hemoglobin molecules to stick together and form long fibers that distort red blood cells into a sickle shape . Hope this helps, and have a great day!