Taxonomially, known number of species is-

Options

A. 1.7 billion
B. 17 lakh
C. 5 to 30 million
D. 17 million

Answer

To determine the taxonomically known number of species, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Taxonomy**: Taxonomy is the branch of science that deals with the classification of organisms. It involves identifying, naming, and classifying species into groups based on shared characteristics.

2. **Identify the Options**: The question provides several options for the number of taxonomically known species:
- 1.7 billion
- 17 lakh
- 5 to 30 million
- 17 million

3. **Research Known Species**: According to scientific estimates, the total number of species that have been described and classified is approximately 17 lakh (1.7 million). This includes:
- Around 12 lakh species of animals
- About 3 lakh species of plants
- Approximately 2 lakh species of microorganisms

4. **Evaluate the Options**:
- **1.7 billion** is significantly higher than the known number of species.
- **5 to 30 million** is a broad range but still does not accurately reflect the known number.
- **17 million** is also higher than the actual number.
- **17 lakh** is the only option that aligns with the known data.

5. **Conclusion**: Therefore, the correct answer is **17 lakh**, which corresponds to option B.

### Final Answer:
The taxonomically known number of species is **17 lakh** (option B).

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