Insects have spiracles. What are spiracles?

Insects have spiracles. What are spiracles?

• A. Grit-like structures on the cuticle that reduce dehydration
• B. Holes or vents in an insect's exoskeleton that allow air to enter for respiration
• C. Jointed appendages for locomotion
• D. Osmoregulatory glands

Answer: (B)

Spiracles are openings in the insect’s outer body wall that connect to the internal respiratory system. They act as entry (and exit) points for gases, letting air move into a branching network of tracheae and tiny tracheoles that deliver oxygen directly to tissues and remove carbon dioxide. The spiracles can be opened or closed by muscles, which helps regulate gas exchange and reduce water loss in dry environments. This is why spiracles are the breathing openings of insects, not structures for dehydration grit, locomotion, or osmoregulation.

Spiracles are openings in the insect’s outer body wall that connect to the internal respiratory system. They act as entry (and exit) points for gases, letting air move into a branching network of tracheae and tiny tracheoles that deliver oxygen directly to tissues and remove carbon dioxide. The spiracles can be opened or closed by muscles, which helps regulate gas exchange and reduce water loss in dry environments. This is why spiracles are the breathing openings of insects, not structures for dehydration grit, locomotion, or osmoregulation.