Answer: (C) Over the course of the year, the tilt of Earth's axis varies from 23.5° to 0° in such a way as to bring more heating per hour in the summer than in the winter
Explanation: The Earth's axis is tilted 23.5 degrees, which causes one of the hemispheres to be closer to the sun, but not only during the day, but at a certain time of the year called summer. When one of the hemispheres is closer to the sun during the day, it is also closer to the sun during the night because one part of that hemisphere is in the dark, but only until morning until the earth turns around its axis.
This means that during the summer, more sunshine hours at certain hemisphere, more heating per hour, so sunbathers can enjoy it, and skiers in the same hemisphere wait until that hemisphere is farther away from the sun, which means less hours of sunshine, cooler weather, maybe even snow, so they can to ski and then enjoy.