Which one of the following fungus shows heterothallism

Options

A. Rhizopus
B. Bacterium
C. Cycas
D. Ricinus

Answer

To solve the question regarding which fungus shows heterothallism, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term "Heterothallism":**
- Heterothallism refers to a condition in fungi where sexual reproduction occurs between two genetically different individuals (thalli). This means that two different mating types are required for reproduction.

2. **Identify the Options Given:**
- The options provided are:
- A) Rhizopus
- B) Bacterium
- C) Cycas
- D) Ricinus

3. **Analyze Each Option:**
- **A) Rhizopus:** This is a genus of fungi known to exhibit heterothallism. It requires two different mating types for sexual reproduction.
- **B) Bacterium:** This is a prokaryotic organism and not a fungus. Therefore, it cannot show heterothallism.
- **C) Cycas:** This is a genus of gymnosperms (plants) and does not relate to fungi.
- **D) Ricinus:** This is a flowering plant (castor bean) and also does not pertain to fungi.

4. **Determine the Correct Answer:**
- Among the options, **Rhizopus** is the only organism that is a fungus and shows heterothallism.

5. **Conclusion:**
- The correct answer to the question is **Rhizopus**.

### Final Answer:
**Rhizopus** shows heterothallism.