Question

what is the function of the immune system? it exchanges oxygen and carbon dioxide. it provides structure for the body. it eliminates waste from the body. it responds when pathogens enter the body.

Explanation:

• Analyze each option:
• "It exchanges oxygen and carbon dioxide." This is the function of the respiratory system, not the immune system.
• "It provides structure for the body." This is the function of the skeletal system.
• "It eliminates waste from the body." This is the function of the excretory system.
• "It responds when pathogens enter the body." The immune system's main function is to defend the body against pathogens (like bacteria, viruses) by responding to their presence.

Answer:

D. It responds when pathogens enter the body.