Which of these is an example of natural selection acting on genetic variation resulting in evolutionary adaptation?As global warming has continued, many species that were found near the tropics have migrated either northward or southward toward the poles.As the African environment became drier and the grasslands more prevalent, arched feet and non-opposable toes, both more effective for walking upright, became more common in hominins.Insect diversity in temperate broadleaf forests varies from year to year based on the amount of precipitation.During years of drought, tree rings are narrower.

As the African environment became drier and the grasslands more prevalent, arched feet and non-opposable toes, both more effective for walking upright, became more common in hominins

Explanation:

According to Darwin's theory of evolution, natural selection is the main evolutionary mechanism. Darwin explains that organisms that have heritable traits that help them survive and reproduce, will be favorable by natural selection. Those favorable traits will enable organism to better adapt to their environment and to pass more genes on to the next generation (offspring). Favorable traits increase organism's fitness. In the example above, resarched feet and non-opposable toes are favorable traits that helped hominini's survival in the drier environment.