This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Which of the following is true about sickle cell red blood cells? \nSelect and explain. \nA. Stability, B. Altered function, C. Decreased oxygen carrying capacity, D. Protective against adult malaria', 'role': 'user'}, {'content': "Answer: D \nExplanation: HbA/S heterozygotes (sickle cell trait) have a sixfold reduction in the risk of dying from severe falciparum malaria. This decrease in risk appears to be related to impaired parasite growth at low oxygen tensions and reduced parasitized red cell cytoadherence. Parasite multiplication in HbA/E heterozygotes is reduced at high parasite densities. Ref: White N.J., Breman J.G., Osler W. (2012). Chapter 210. Malaria. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.", 'role': 'assistant'}]