Final answer:
The immune system prevents disease by fighting bacteria that produce substances toxic to the body.
Step-by-step explanation:
The bacteria that produce substances toxic to the body can be fought by the immune system. The immune system is made up of various cells and molecules that work together to recognize and eliminate harmful bacteria. For example, white blood cells called phagocytes can engulf and destroy bacteria, while antibodies can neutralize toxins produced by bacteria. These immune responses help prevent disease by combating the bacteria and toxins that can harm the body.