Complete the statement:
Malpighian tubules help in removal of _____________

Explanation

**Step-by-Step Solution:**

1. **Identify the Structure**: Malpighian tubules are excretory structures found in insects, particularly prominent in cockroaches.

2. **Understand Their Function**: The primary function of Malpighian tubules is to remove waste products from the insect's body.

3. **Determine the Type of Waste**: The waste that is primarily removed by Malpighian tubules is nitrogenous waste.

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