Heterothallism was first discovered by

Options

A. Blakeslee
B. Mehta
C. Pasteur
D. Alexopolous

Answer

To solve the question "Heterothallism was first discovered by," we can follow these steps:

### Step-by-Step Solution:

1. **Understand the term "Heterothallism":**
- Heterothallism refers to a condition in algae where the male and female reproductive organs are located on different thalli (plural of thallus). This means that two separate organisms are required for reproduction.

2. **Identify the options given:**
- Option 1: Black algae
- Option 2: Mehta
- Option 3: Pasteur
- Option 4: Exopolar

3. **Recall the discovery of Heterothallism:**
- According to the information provided, Heterothallism was first discovered by a scientist named Black Kelsey in the year 1904.

4. **Select the correct option:**
- Based on the information, the correct answer is **Black Kelsey** (which corresponds to the first option, Black algae).

5. **Conclude the answer:**
- Therefore, the answer to the question "Heterothallism was first discovered by" is **Black Kelsey**.

### Final Answer:
Heterothallism was first discovered by Black Kelsey.

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