Number of known and described species is

Options

A. `1.7-1.8` million
B. `1.7-1.8` lac
C. `1.7-1.8` billion
D. `17-18` million

Answer

To answer the question regarding the number of known and described species, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for the number of known and described species in the world.

2. **Review the Options**: The provided options are:
- A) 1.7 to 1.8 million
- B) 1.7 to 1.8 lakh
- C) 1.7 to 1.8 billion
- D) 17 to 18 million

3. **Identify the Correct Range**: From biological studies and data, it is known that the estimated number of known and described species is approximately between 1.7 to 1.8 million.

4. **Consider Additional Information**: It is noteworthy that a significant percentage of these species are insects (about 61%), and around 15,000 new species are discovered each year.

5. **Select the Correct Option**: Based on the information, the correct answer is option A) 1.7 to 1.8 million.

### Final Answer:
The number of known and described species is approximately **1.7 to 1.8 million**.

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