Question

In cockroaches, air enters the body through

• A. Lungs
• B. Gills
• C. Spiracles
• D. Skin

Answer 1

The correct option is C

Spiracles

The correct option is C.

Explanation for the correct option:

Option C:

1. A cockroach has 8 abdominal and 2 thoracic spiracles.
2. When a cockroach exchanges gas, stigmata, which are unique valves with tubules, allow ambient air to enter and exit.
3. There are 20 spiracles, 2 pairs of which are located in the thoracic region and the remaining 8 pairs in the abdomen region.
4. The cockroach's respiratory system is made up of a network of the trachea that opens through ten pairs of tiny openings on its side known as spiracles.
5. All the organs receive oxygen from the air through thin branching tubes called tracheoles.
6. Spiracles are the body's air entry points.
7. The pressure inside the system is known to be balanced by the tracheae.
8. Oxygen-rich air diffuses into the cockroach's numerous tissues and cells when it enters the body through spiracles and tracheal tubes.
9. Here, oxygen is depleted to release energy.
10. Similar to this, air that is high in carbon dioxide enters the trachea and exits through the spiracles.
11. The respiratory process results in the release of carbon dioxide.
    

Explanations for the incorrect options:

Option A:

1. The cockroach lacks lungs, much like other insects.
2. Instead, it has a network of tubes called tracheae that open at the surface of the thorax and abdomen through paired valve-like structures called spiracles.
3. All land-based vertebrate animals have lungs.

Option B:

1. Many aquatic species use their gills as respiratory organs to take in dissolved oxygen from the water and expel carbon dioxide.
2. With very few exceptions, all animals that live in water breathe through gills.
3. Mollusks, crustaceans, insects, fish, and amphibians are a few examples of aquatic organisms that have gills or gill-like organs that can be found in various sections of the body.

Option D:

1. Skin has three major purposes: protection, regulation, and feeling.
2. It is a layer of typically soft, flexible outer tissue that covers the body of a vertebrate animal.
3. Provides a barrier of defense against harmful substances, mechanical, thermal, and physical harm.
4. Prevents moisture loss

Final answer: In cockroaches, air enters the body through spiracles.