In the short span of time where Man have studied natural history, all forms of life have been noted to have some changes in its form in the process of 'Adaptation'. The popular Hawaiian Honeycreepers are often quoted in textbooks, where the various finch species, distributed widely over many islands in the archipelago, each have evolved variation in structure in its toes and beaks according to their diet and mode of feeding. Man, too, have to change according to the changing environment. In Man, it is believed that the rudimentary organ such as the human appendix has a proper digestive use in the past. Dark skin has its function in protecting Man from ultra-violet light.
Swimmers have 'flat-foot'.
Let me not take the fun out of your homework or assignment. You may think of other examples of Adaptation that could well be a feature of the human kind as Man changes according to the external environment. Observe, analyse, and conclude. Be a scientist.