Select incorrect statement w.r.t the following group of organisms and their characteristics

Options

A. Chyrophyte - Includes diatoms and desmids, Planktonic organism
B. Dinoflagellate - Mostly marine and photosynthetic, cell wall has stiff cellulosic plate on outer surface
C. Euglenoids - Majority of them are fresh water, cell wall is absent
D. Slime mould - Saprophytic motile spores with true walls

Answer

To solve the question of identifying the incorrect statement regarding the group of organisms and their characteristics, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Analyze the First Statement:**
- **Statement:** Chirophytes and their characteristics include diatoms and desmids.
- **Analysis:** Chirophytes (often referred to as green algae) do include organisms like diatoms and desmids. They are primarily found in aquatic environments and are photosynthetic. This statement is correct.

2. **Analyze the Second Statement:**
- **Statement:** Dinoflagellates are mostly marine and photosynthetic. Cell wall has stiff cellulosic plates on the outer surface.
- **Analysis:** Dinoflagellates are indeed mostly marine organisms, and many are photosynthetic. Their cell wall is composed of stiff cellulosic plates. This statement is also correct.

3. **Analyze the Third Statement:**
- **Statement:** Euglinoids - Majority of them are freshwater; cell wall is absent.
- **Analysis:** Euglinoids, such as Euglena, are primarily found in freshwater environments. They do not have a cell wall but have an elastic protein covering known as a pellicle. This statement is correct.

4. **Analyze the Fourth Statement:**
- **Statement:** Slime molds, saprophytic motile spores with true walls.
- **Analysis:** Slime molds are saprophytic and feed on decaying organic matter. However, the spores produced by slime molds are not motile; they are dispersed through air currents. Additionally, these spores do have cell walls. Therefore, the claim that they are "motile" is incorrect.

### Conclusion:
The incorrect statement is the fourth one regarding slime molds.

### Final Answer:
**D: Slime molds, saprophytic motile spores with true walls.**

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