Question

1. choose the best answer.

one of the benefits of diet and activity is an improved ____, which helps the body fight
contagious diseases.
heart strength
immune system
respiration system
digestion system

Explanation:

A strong immune system helps the body fight contagious diseases. Diet and activity can improve the immune system. The other options (digestion system, respiration system, heart strength) are not directly related to fighting contagious diseases in the context of the question.

Answer:

immune system