The total number of species, that are known and described , range between:

Options

A. 1.7 – 1.8 lac
B. 17 – 18 million
C. 7 – 8 million
D. 1.7 – 1.8 million

Answer

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

### Step 1: Understand the Question
The question asks for the range of the total number of species that are known and described. This includes all types of organisms.

### Step 2: Analyze the Options
We have four options to consider:
1. 1.7 to 1.8 lakh
2. 17 to 18 million
3. 7 to 8 billion
4. 1.7 to 1.8 million

### Step 3: Recall Relevant Information
From biological studies and current research, it is known that approximately 1.7 to 1.8 million species have been described. This includes various organisms, with a significant portion being insects.

### Step 4: Eliminate Incorrect Options
- **1.7 to 1.8 lakh**: This is too low, as it translates to 170,000 to 180,000 species.
- **17 to 18 million**: This is too high, as it exceeds the known number of described species.
- **7 to 8 billion**: This is unrealistic, as it far exceeds any estimates of known species.
- **1.7 to 1.8 million**: This matches the known data about described species.

### Step 5: Conclusion
Based on the analysis, the correct answer is **1.7 to 1.8 million**. This range accurately reflects the total number of species that are currently known and described.