During a Zoology practical, a grasshopper delivers oxygen directly to tissues through branching air tubes. Select the most accurate identification.

Correct Answer: A

tracheal system

Insects use a tracheal respiratory system made of tubes opening through spiracles. Oxygen reaches tissues directly, reducing reliance on blood for oxygen transport. This MCQ belongs to the Insecta topic in Animal Diversity-I and is written to test concept understanding rather than memorized wording.