John has noticed that many people in his generation tend to be overweight, while pictures of people from older generations show healthy weights when they were his age. what is the most likely reason he is more susceptible to illness?

Well, if you are able to put it in your own words, centuries back, when are ancestors were alive, we didn’t have things like McDonald’s. For a lot of people back then, they wouldn’t eat for a day or two then find a buffalo or something then eat it, and most of the time, they were running all day every day trying to find food. Getting lots of exercise. Nowadays, u can get into your car, and drive to A fast food place and get whatever u want. With no exercise.