Thick walled spores are formed in unfavourable conditions in :

Options

A. Bacteria
B. Fungi
C. Lower plants
D. All of these

Answer

To answer the question about which organisms form thick-walled spores in unfavorable conditions, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Unfavorable Conditions**:
- Organisms often face unfavorable conditions such as extreme temperatures, drought, or lack of nutrients. In response to these conditions, they need to find ways to survive.

2. **Survival Mechanisms**:
- To survive, many organisms suspend their metabolic activities. This allows them to endure periods when conditions are not conducive to growth or reproduction.

3. **Formation of Spores**:
- One common survival strategy is the formation of spores. Spores are reproductive units that can withstand harsh conditions. They often have thick walls that protect them from environmental stressors.

4. **Types of Organisms**:
- Various organisms produce thick-walled spores in response to unfavorable conditions. This includes:
- **Bacteria**: Certain bacteria can form endospores, which are highly resistant to extreme conditions.
- **Fungi**: Many fungi produce thick-walled spores (like zygospores or ascospores) to survive adverse conditions.
- **Lower Plants**: Some lower plants, including certain algae, also produce spores to endure unfavorable environments.

5. **Conclusion**:
- Based on the information, the correct answer to the question is that thick-walled spores are formed in unfavorable conditions in various organisms, specifically in bacteria, fungi, and lower plants.

6. **Final Answer**:
- The correct option is **all of the above** (option no. 4).