Which of the following statements regarding slime moulds is true ?

Options

A. They show autotrophic mode of nutrition.
B. The spores produced by them in harsh environments, possess true walls.
C. Slime moulds form aggregation called vegetation.
D. The spores produced by them require water for dispersal.

Answer

To determine which statement regarding slime moulds is true, let's analyze each statement step by step.

1. **First Statement: "They show autotrophic mode of nutrition."**
- Slime moulds belong to the kingdom Protista and are primarily saprophytic. This means they feed on dead organic matter, rather than producing their own food through photosynthesis (autotrophy). Therefore, this statement is **not true**.

2. **Second Statement: "The spores produced by them in harsh environment possess true walls."**
- In harsh environmental conditions, slime moulds do produce spores that have protective walls. These walls help the spores survive until conditions improve. This statement is **true**.

3. **Third Statement: "Slime moulds form aggregation called vegetation."**
- Slime moulds can form aggregations, but these are referred to as plasmodium, not vegetation. Therefore, this statement is **not true**.

4. **Fourth Statement: "Spores produced by them require water for disposal."**
- Slime mould spores do not require water for their dispersal; they can be carried by air currents. Thus, this statement is also **not true**.

After analyzing all the statements, we find that the only true statement regarding slime moulds is the second one: "The spores produced by them in harsh environment possess true walls."

### Final Answer:
The correct statement is: "The spores produced by them in harsh environment possess true walls."

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