A Level Biology Practice Exam 2025 – All-in-One Study Guide to Excel in Your A Levels!

Spiracles are small openings located on the exoskeleton of insects, primarily used for gas exchange. They play a crucial role in the respiratory system of insects, allowing oxygen to enter the body and carbon dioxide to exit. Insects do not possess lungs like vertebrates; instead, they have a network of tubes known as tracheae that deliver oxygen directly to their tissues. The spiracles serve as the entry and exit points for the gases involved in respiration, making them essential for Metabolic processes.

While reproduction, water storage, and nutrient absorption are important functions in various organisms, they are not the roles of spiracles in insects. Reproductive structures and processes occur in entirely different anatomical areas, while water storage and nutrient absorption are managed by specialized systems such as the digestive tract and excretory organs, rather than through spiracles. Hence, gas exchange is the specific and vital function of spiracles in insects.