In sickle-cell disease, variation in one gene causes red blood cells to bend, or sickle. This means the sickled cells .

A case study of the effects of mutation: Sickle cell anemia. Sickle cell anemia is a genetic disease with severe symptoms, including pain and anemia. The disease is caused by a mutated version of the gene that helps make hemoglobin — a protein that carries oxygen in red blood cells.

Explanation:

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%