select the odd one w.r.t. the MOS which is a good many and has great water holding capacity.

Options

A. Bog moss
B. Peat moss
C. Cotton moss
D. Irish moss

Answer

To solve the question of selecting the odd one out with respect to mosses that have good water holding capacity, we can analyze each option provided:

1. **Bog Moss (Sphagnum)**:
- Sphagnum moss is known for its exceptional water retention capabilities. It can hold water up to 16 to 26 times its dry weight due to specialized structures called vacuoles. This makes it one of the best mosses for water retention.

2. **Peat Moss**:
- Peat moss also has a high moisture storage capacity. It can retain about 10 times more water than many other plants. This makes it another strong contender for high water holding capacity.

3. **Cotton Moss**:
- Cotton moss is known for its ability to store moisture as well. It has a good water retention quality, making it effective in holding water.

4. **Irish Moss**:
- Irish moss, in contrast, does not have a good water holding capacity. It is noted that it does not improve soil quality and has a low ability to absorb water compared to the other mosses mentioned.

**Conclusion**: Based on the analysis, the odd one out is **Irish Moss** because it has the lowest water holding capacity compared to Bog Moss, Peat Moss, and Cotton Moss.

### Steps:
1. Identify the characteristics of each type of moss regarding water retention.
2. Compare the water holding capacities of Bog Moss, Peat Moss, Cotton Moss, and Irish Moss.
3. Determine which moss has the least capacity for water retention.
4. Conclude that Irish Moss is the odd one out.