<a href=https://explorable.com/cause-and-effect>Establishing Cause and Effect</a>. Cause and effect is one of the most commonly misunderstood concepts in science and is often misused by lawyers, the media, politicians and even scientists themselves, in an attempt to add legitimacy to research.
You can't catch cancer from anyone, in any way. Cancer is not contagious. You can't catch HIV/AIDS just by touching somebody. The AIDS virus is not found in sweat. Yes, you can catch a cold, or the flu by shaking hands with someone if you then put your hands on/near a mucous membrane (eyes, nose, mouth).
Essential tremor mainly involves your hands, head and voice. Parkinson's disease tremors usually start in your hands, and can affect your legs, chin and other parts of your body. Causes. About half of essential tremor cases appear to result from a genetic mutation, although a specific gene hasn't been identified.