Read the below statements and select the appropriate option.
a. Experimental removal of Pisaster resulted in the extinction of more than species of invertebrates.
b. Nearly 20 percent of all insects are known to be phytophagous.
c Predators help to maintain species diversity.

Options

A. Both a and c are correct
B. b is correct but c is incorrect
C. a is correct but b is incorrect
D. only c is correct

Answer

To solve the question, we need to evaluate the three statements provided and determine their correctness.

### Step-by-Step Solution:

1. **Evaluate Statement A**:
- "Experimental removal of Pisaster resulted in the extinction of more than species of invertebrates."
- This statement is **correct**. The removal of the Pisaster starfish from the American Pacific coast led to a significant decline in biodiversity, resulting in the extinction of more than 10% of invertebrate species.

2. **Evaluate Statement B**:
- "Nearly 20 percent of all insects are known to be phytophagous."
- This statement is **correct**. Phytophagous insects, which feed on plants, do indeed make up a significant portion of the insect population, and estimates suggest that around 20% is a reasonable approximation.

3. **Evaluate Statement C**:
- "Predators help to maintain species diversity."
- This statement is also **correct**. Predators play a crucial role in ecosystems by controlling prey populations, which helps maintain a balance and promotes species diversity.

### Conclusion:
All three statements (A, B, and C) are correct. However, since the question asks for the appropriate option based on the correctness of the statements, we can conclude that the correct answer is:

**Option A: Both A and C are correct.**