Final answer:
Insects use a tracheal system with spiracles to transport gases throughout the body, and the trachea is a part of their respiratory system, not the digestive system.
Step-by-step explanation:
Insects employ an intricate tracheal system for gas exchange, transporting oxygen directly to their cells without the need for lungs. This system comprises a network of small tubes that branch throughout the insect's body, facilitating efficient respiration. The main tracheae open to the external environment through small apertures known as spiracles, typically located on the insect's abdomen and thorax.
Contrary to the given options, the false statement is indeed c: The trachea is part of the digestive system. In insects, the trachea is a crucial component of the respiratory system, not the digestive system. The tracheal tubes function to transport gases, facilitating the exchange of oxygen and carbon dioxide between the insect's body cells and the external environment. This adaptation allows insects to respire without the need for respiratory organs such as lungs, showcasing the remarkable diversity of respiratory strategies in the animal kingdom.