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

Which factor is NOT typically considered when assessing environmental effects on plants?

1. Rainfall/water availability

2. Pollution levels

3. Predator species presence

4. pH levels

The correct answer is: Predator species presence

When assessing environmental effects on plants, factors such as rainfall or water availability, pollution levels, and pH levels are considered critical because they directly influence plant growth, health, and distribution. Rainfall is essential for hydration and nutrient uptake, pollution can affect plant physiological processes and lead to damage, and pH levels of the soil can affect nutrient availability and toxicity. In contrast, while predator species presence can affect herbivory (the consumption of plants by animals) and indirectly influence plant populations, it is not a primary environmental factor in the same direct way as the others mentioned. Thus, this option is often seen as less relevant when evaluating how plants directly interact with their environment on a broad scale.