In regions where malaria is prevalent, the s allele is beneficial because: it causes red blood cells to distort, which makes them less hospitable to plasmodium, the parasite that causes malaria. it prevents mosquitoes from releasing plasmodium, the mosquito that causes malaria, into the blood. it improves the ability of the hemoglobin to carry oxygen. it improves the ability of the immune system to fight plasmodium, the parasite that causes malaria.

African penguins, which inhabit the coasts of southern africa, were classified as an endangered species in 2010. two significant threats to their survival are ecosystem damage from oil spills and overfishing by humans. overfishing depletes the food supply of african penguins. the best method to reduce the threat of overfishing would be to . the risk of oil spills could be reduced by increasing the use of , which should oil consumption. if an oil spill does occur, could be used to remove the oil so the ecosystem may more quickly recover.