What is the total number of species present on earth as estimated by Robert May ?
(a) 3 million
(b) 5 million
(c) 7 million
(d) 9 million

Options

A. 3 million
B. 5 million
C. 7 million
D. 9 million

Explanation

To solve the question regarding the total number of species present on Earth as estimated by Robert May, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Context**: The question asks for the estimated number of species on Earth according to Robert May. It's important to note that there have been various estimates over time regarding the total number of species.

2. **Identify Initial Estimates**: Initially, some estimates suggested that there could be between 20 to 50 million species on Earth. However, these were not based on scientific consensus.

3. **Look for Robert May's Contribution**: Robert May provided a more conservative and scientifically backed estimate. This is crucial as the question specifically asks for his estimation.

4. **Recall Robert May's Estimate**: According to the video transcript, Robert May estimated that there are approximately 7 million species on Earth. This number is significantly lower than the initial estimates mentioned earlier.

5. **Determine the Correct Option**: Based on the information provided, the correct answer to the question is (c) 7 million.

### Final Answer:
The total number of species present on Earth as estimated by Robert May is (c) 7 million.

---