OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What leads to a decrease in daylight hours during autumn?

1. The distance of the Earth from the sun increases

2. The tilt of the Earth's axis changes

3. The sun rises later and sets earlier

4. The Earth rotates slower

The correct answer is: The sun rises later and sets earlier

The correct answer relates to the phenomenon of the sun rising later and setting earlier during the autumn months. As autumn approaches, the position of the Earth relative to the sun changes due to the tilt of the Earth's axis. This tilt causes the sun to take a lower path across the sky. As a result, the daylight hours become shorter since the sun rises later in the morning and sets earlier in the evening, leading to a decrease in the total amount of daylight received each day. The other options do not accurately represent the reason for decreased daylight in autumn. While the tilt of the Earth’s axis plays a significant role in the seasonal changes, it does not change during the season itself. The distance of the Earth from the sun does affect the seasons, but it is not a direct cause of the changes in daylight hours we observe. The Earth’s rotation speed does not significantly change in a way that would affect the length of a day during the seasons. Thus, option C accurately captures the essence of the decrease in daylight hours experienced in autumn.