Some genetic disorders, such as sickle cell disease, are due to?

I didn't know how to explain it very well so I had goog.le help me:

Sickle cell disease is caused by a mutation in the hemoglobin-Beta gene found on chromosome 11. Red blood cells with normal hemoglobin  are smooth and round and glide through blood vessels.

c. movement because i took the test and it lets me review my answers

the atmospheric gas that forms a mild acid when dissolved in water is called carbon dioxide. the correct answer is a. 2.) chemical weathering would cause an inscription on a marble headstone to become harder and harder to read over time.