What is the apparatus by which insects breathe?

What is the apparatus by which insects breathe?

• A. Gills
• B. Mouthparts
• C. Trachea
• D. Spiracles

Answer: (D)

Insects breathe through a set of external openings called spiracles that connect to an internal network of air tubes—the tracheal system. Air enters the body via these openings, travels down progressively finer tubes (tracheae and then tracheoles), and oxygen diffuses directly to tissues. This setup means they don’t rely on lungs or gills. Gills are used by aquatic animals, mouthparts are for feeding, and while insects do have internal tracheae, the important gateway for air is the spiracle—the entry point to respiration.

Insects breathe through a set of external openings called spiracles that connect to an internal network of air tubes—the tracheal system. Air enters the body via these openings, travels down progressively finer tubes (tracheae and then tracheoles), and oxygen diffuses directly to tissues. This setup means they don’t rely on lungs or gills. Gills are used by aquatic animals, mouthparts are for feeding, and while insects do have internal tracheae, the important gateway for air is the spiracle—the entry point to respiration.