Question

Which one of the following is not true about the human respiratory system?

• A. It maintains acid balance
• B. It maintains oxygen and carbon-dioxide balance
• C. It meets the higher oxygen demands
• D. There is a direct contact between all body cells and the surrounding air

Answer 1

The correct option is D

There is a direct contact between all body cells and the surrounding air

In the human respiratory system, the body cells are not in direct contact with the air or water as seen in worms or insects. Small animals whose cells make direct contacts with the environment, carry out gas exchange by diffusion. Larger animals, whose cells are not in direct contact with the environment, need special gas transportation systems.