[Campbell Biology P.991] According to the provided text, what is the primary purpose of the ... | Practice Question

According to the provided text, what is the primary purpose of the fluid withdrawal from the closed ends of tracheoles when an insect becomes active and uses more O2?

  • A: To reduce the overall volume of the tracheal system, making it more efficient for rapid air pumping.
  • B: To increase the surface area of air-filled tracheoles in direct contact with body cells, enhancing gas exchange.
  • C: To prevent the accumulation of metabolic waste products in the tracheoles.
  • D: To regulate the insect's internal body temperature by evaporating excess fluid.

Explanation

The text explicitly states regarding tracheoles: 'When the animal is active and using more O2, most of the fluid is withdrawn into the body. This increases the surface area of air-filled tracheoles in contact with cells.' This directly supports option B as the primary purpose.