What percentage of all insects is known to be phytophagous?

Options

A. Nearly 75%
B. Nearly 25%
C. Nearly 2%
D. Nearly 90%

Answer

To solve the question of what percentage of all insects is known to be phytophagous, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Term "Phytophagous":**
- Phytophagous refers to organisms, particularly insects, that feed on plants. This includes various parts of plants such as leaves, stems, roots, and branches.

2. **Identify the Number of Phytophagous Insect Species:**
- It is noted that there are approximately 500,000 species of insects that are categorized as phytophagous.

3. **Determine the Total Number of Insect Species:**
- While the exact total number of insect species is not provided in the transcript, it is widely accepted that there are about 1 million described species of insects, with estimates suggesting there could be up to 10 million species in total.

4. **Calculate the Percentage of Phytophagous Insects:**
- To find the percentage of phytophagous insects, we can use the formula:
\[ \text{Percentage of Phytophagous Insects} = \left( \frac{\text{Number of Phytophagous Species}}{\text{Total Number of Insect Species}} \right) \times 100 \]
- Using the approximate numbers:
\[ \text{Percentage} = \left( \frac{500,000}{1,000,000} \right) \times 100 = 50\% \]
- However, the transcript states that approximately 25% of total insects are phytophagous, which aligns with more conservative estimates based on various studies.

5. **Conclusion:**
- Therefore, the answer to the question is that approximately 25% of all insects are known to be phytophagous.

### Final Answer:
Approximately 25% of all insects are known to be phytophagous.

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