Answer:d. the sickle-cell allele can impact many different body systems
Explanation:sickle cell anaemia is the shortage of red blood cells.red bloods cells functions to carry oxygen through out the body aided by the haemoglobin.when however a person has sickle cell anaemia,his red blood cells become abnormal.they are no longer flexible and round ,they become stiff and sickle-shaped.when this changes in the red blood cell occurs,it is no longer flexible to pass through the blood vessels,causing the blockage of the vessels and the red blood cells break apart easily ,causing its shortage in the body.as body organs need oxygen to survive, people with sickle cell anaemia tends to have organ failures,pain crises , infections etc.