What is the role of organic matter in soil?

1. Organic matter is decayed plant and animal material held in the soil. 2. It stores plant nutrients and releases them gradually, which is what makes a soil fertile. 3. Water infiltration depends on soil porosity, a physical property, rather than on organic matter. 4. Breaking down organic matter is the work of soil micro-organisms, so that option swaps the roles round. 5. Converting nitrogen to nitrate is nitrification, carried out by bacteria and not driven by organic matter itself. _Source: NECTA CSEE 2021 Chemistry 032, Question 1: Multiple Choice, item (viii)_