Diseases are a disorder of structure or function in a human especially one that produces specific signs or symptoms or that affects a specific location and is not simply a direct result of physical injury.
A lot of diseases can be cure with vaccine, which is like medicine that makes the disease go away. But sometimes it doesn't work. Also sometimes there is no vaccine like HIV doesn't have a cure.
Alcohol is actually really bad, it can mess up your immune system to where it can't fight off diseases. It's okay to have one or two in a day but no more than that.
Exercising is a major part in helping your body fight off diseases. It helps by making your immune system a lot stronger. It's like the opposite oh alcohol because instead helping diseases it fights against them.