Earth is tilted as it travels around the Sun. The tilt changes the amount of energy each area gets from the Sun, which makes some months of the year warmer than others. What are the four main temperature changes in a year called?

The questions have been asked in several important state and regional science exams in the United States. For example: TAKS-Texas Assessment of Knowledge and Skills, New York State Educational Department Regents exams, California Standards Test, etc.