Answer:
The presence of insulin resistance genes and sickle cell alleles demonstrate human evolution because they are both examples of genetic adaptations that have occurred in response to changes in the environment. Insulin resistance genes are believed to have been selected for in populations where food was scarce and where sugar was not a primary source of energy. This allowed individuals to better survive famine conditions. Sickle cell alleles, on the other hand, are believed to have been selected for in populations living in regions with high levels of malaria. This allele helps protect individuals from malaria by making it difficult for the malaria parasite to enter red blood cells. Both of these genetic adaptations demonstrate how humans have evolved in response to their environment over time.
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