Which structure of man is similar to spiracle of cockroach?

Options

A. Nostril
B. Bronchiole
C. Lung
D. Alveolus

Explanation

To answer the question "Which structure of man is similar to the spiracle of cockroach?", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Spiracles**: First, we need to understand what spiracles are. Spiracles are small openings located on the surface of the cockroach's body that allow air to enter the tracheal system. They are crucial for respiration in insects.

2. **Identifying the Respiratory System of Cockroach**: The cockroach has a tracheal system which consists of a network of tubes (tracheae) that transport air directly to the tissues. The spiracles serve as the entry points for air into this tracheal system.

3. **Finding a Similar Structure in Humans**: Now, we need to identify a similar structure in humans that serves the same purpose of allowing air to enter the respiratory system. In humans, air enters through the nostrils.

4. **Conclusion**: The nostrils in humans are analogous to the spiracles in cockroaches. Just as spiracles allow air to enter the tracheal system of cockroaches, nostrils allow air to enter the nasal cavity and subsequently the lungs in humans.

### Final Answer:
The structure in humans that is similar to the spiracle of a cockroach is the **nostrils**.

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