Micro-organism act upon the dead plant to produce :

Question

Accepted Answer

Micro-organisms, such as bacteria and fungi, play a crucial role in the decomposition process of dead plants. When plants die, these micro-organisms break down the complex organic materials present in the plant tissues. This process of decomposition results in the formation of humus, which is a dark, organic material that enriches the soil. Humus is essential for maintaining soil fertility as it improves soil structure, retains moisture, and provides nutrients for plant growth. Therefore, Option 3, "Humus," is the correct answer because it accurately describes the product of micro-organisms acting upon dead plant matter.

Now, let's examine why the other options are incorrect:

1. **Mushroom**: Mushrooms are a type of fungi that can grow on decaying organic matter, but they are not the direct product of micro-organisms decomposing dead plants. Instead, mushrooms themselves are decomposers that contribute to the breakdown process.

2. **Sand**: Sand is a granular material composed of finely divided rock and mineral particles. It is not produced by the decomposition of organic matter by micro-organisms. Sand is a component of soil but is not related to the decomposition of dead plants.

3. **Wood**: Wood is the hard, fibrous structural tissue found in the stems and roots of trees and other woody plants. It is not a product of decomposition; rather, it is part of the plant structure that can be broken down by micro-organisms after the plant dies.

In summary, micro-organisms decompose dead plant material to produce humus, which is why Option 3 is the correct answer. The other options do not accurately describe the outcome of this decomposition process.