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

In what way can light intensity affect plant distribution?

1. It determines the amount of precipitation

2. It influences the rate of photosynthesis

3. It directly modifies soil structure

4. It controls the amount of CO2 in the atmosphere

The correct answer is: It influences the rate of photosynthesis

Light intensity plays a crucial role in influencing the rate of photosynthesis, which is the process by which plants convert light energy into chemical energy. This energy is essential for plant growth and survival. When light intensity is high, photosynthesis occurs at a faster rate, allowing plants to produce more glucose and oxygen. This ability to efficiently produce energy can directly affect where certain plant species thrive. Plants that require higher light levels may be found in well-lit areas where they can maximize photosynthesis, while shade-tolerant species may be able to grow in lower light conditions. As such, variations in light intensity can lead to differences in plant distribution in various ecosystems. For instance, areas with high light availability can support a diverse range of plants, while shaded regions may support different species adapted to survival in lower light. The other options provided relate to different environmental factors that do not have a direct link to how light intensity affects plant distribution through the process of photosynthesis.