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

How do forests contribute to maintaining the greenhouse effect?

1. By absorbing carbon dioxide through photosynthesis

2. By increasing the greenhouse gas emissions

3. By preventing the formation of clouds

4. By promoting the growth of harmful plants

The correct answer is: By absorbing carbon dioxide through photosynthesis

Forests play a crucial role in maintaining the greenhouse effect primarily through their ability to absorb carbon dioxide during the process of photosynthesis. Trees and other plants take in carbon dioxide from the atmosphere and convert it into oxygen and glucose, effectively reducing the concentration of this greenhouse gas. This process is vital because carbon dioxide is one of the primary contributors to the greenhouse effect, trapping heat in the atmosphere and leading to global warming. By sequestering carbon dioxide, forests help mitigate climate change and maintain a balance in the greenhouse gases present in the atmosphere. This natural mechanism is essential for sustaining healthy ecosystems and regulating the Earth's temperature. The contributions of forests to the greenhouse effect are significant, especially considering the increasing levels of carbon emissions from human activities. In contrast, the other options don’t accurately depict the beneficial role forests hold in this context. For instance, increasing greenhouse gas emissions would have a negative impact, and preventing cloud formation does not relate to the greenhouse effect directly. Moreover, the promotion of harmful plants detracts from the positive environmental impact forests provide.