The electron micrograph shows some of the airways in the gaseous exchange system of an insect and the respiring body cells that surround them. Which statements describe correct differences between the insect gas exchange system shown in the electron micrograph and the human gas exchange system? 1 Gas exchange occurs through the walls of the airways directly into respiring body cells in insects but this does not occur in humans. 2 There are spirals of chitin in the walls of a trachea in insects to hold it open but not in humans. 3 There is more than one trachea in the gas exchange system of the insect but only one in humans.

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