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

What causes the seasons to change throughout the year?

1. The variation in Earth's distance from the sun

2. The tilt of the Earth in relation to the sun

3. The speed of the Earth's rotation

4. The gravitational pull of other planets

The correct answer is: The tilt of the Earth in relation to the sun

The seasons change throughout the year primarily due to the tilt of the Earth in relation to the sun. The Earth is tilted on its axis at an angle of approximately 23.5 degrees. As the Earth orbits the sun, this tilt allows different parts of the Earth to receive varying amounts of sunlight at different times of the year. During summer in the Northern Hemisphere, the North Pole is tilted toward the sun, resulting in longer days and more direct sunlight, which leads to warmer temperatures. Conversely, during winter, the North Pole is tilted away from the sun, resulting in shorter days and less direct sunlight, causing cooler temperatures. This axial tilt is responsible for the cyclical pattern of seasons, with spring and autumn occurring in between, as the tilt and the Earth’s orbit create transitional periods of temperature and daylight. This concept is essential for understanding the climate patterns and ecological changes that occur as the seasons progress. Other factors like the Earth's distance from the sun and its rotation may influence temperature and weather but do not directly cause the seasonal changes as vividly as axial tilt does.