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

What role do worms play with DOM?

1. Transform it into fossil fuel

2. Store it in their bodies as energy

3. Nibble and grind it up to aid decomposition

4. Prevent its decomposition entirely

The correct answer is: Nibble and grind it up to aid decomposition

Worms play a crucial role in the decomposition process by nibbling and grinding up decomposing organic matter, known as dead organic matter (DOM). This activity increases the surface area of the DOM, making it more accessible for microorganisms, such as bacteria and fungi, which further break down the material. By enhancing the decomposition process, worms facilitate nutrient cycling in ecosystems, allowing essential nutrients to return to the soil, promoting plant growth. Their action significantly contributes to the health of soil ecosystems and supports overall biodiversity. Other roles mentioned, like transforming DOM into fossil fuels or storing it as energy, do not accurately reflect how worms interact with organic material. Worms do not prevent decomposition; rather, they actively encourage it by breaking down organic matter. This makes their role pivotal in maintaining ecological balance and soil fertility.