Robert May estimated the global species diversity as

Options

A. 7-million
B. 1.5 million
C. 20 million
D. 50 million

Answer

To solve the question regarding Robert May's estimation of global species diversity, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for Robert May's estimation of global species diversity. We need to identify the correct figure from the given options.

2. **Identify the Relevant Information**: According to the video transcript, Robert May estimated the global species diversity to be around 7 million. This is a key piece of information that directly answers the question.

3. **Compare with Other Estimates**: The transcript mentions that the International Union for Conservation of Nature (IUCN) reported approximately 1.5 million species. Additionally, it mentions that other scientists have estimated the global species diversity to be between 20 to 50 million. However, these figures are not relevant to Robert May's estimation.

4. **Select the Correct Answer**: Based on the information provided, the correct answer to the question is 7 million, as this is specifically attributed to Robert May.

5. **Final Confirmation**: To ensure accuracy, we can confirm that the other options (1.5 million, 20 million, and 50 million) do not pertain to Robert May's estimation but rather to other reports or estimates.

### Final Answer:
Robert May estimated the global species diversity as **7 million**.

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