1.1 Express this as a chemical equation 1.2 Indicate THREE functions of carbon dioxide 2 Name the gas responsible for each of the function below: 2.1 Inaccessible compounds become accessible to plant

1.1.1 Express this as a chemical equation

$$\text{CO}_2(g) + \text{H}_2\text{O}(l) \rightarrow \text{H}_2\text{CO}_3(aq)$$

1.1.2 Indicate THREE functions of carbon dioxide

• It reacts with water to form carbonic acid, which helps in the dissolution of soil minerals, making nutrients accessible to plant roots.
• It is a product of root respiration and microbial decomposition of organic matter in the soil.
• It influences soil pH, which in turn affects nutrient availability and microbial activity.

1.2 Name the gas responsible for each of the function below:

1.2.1 Inaccessible compounds become accessible to plant roots

• Carbon dioxide (due to its reaction with water to form carbonic acid, which dissolves minerals)

1.2.2 slows down oxidation

• Nitrogen (as an inert gas, it dilutes oxygen in the soil air)

1.2.3 improves the formation of humus in the soil

• Carbon dioxide (through the formation of carbonic acid, which aids in the breakdown and transformation of organic matter into stable humus)