Washing your mouth regularly is the single most effective way to protect yourself from catching or spreading disease.

This is a false statement. Washing one's hands is a more prudent action to take that would stop the spread or reception of diseases. While washing one's mouth can help in some respects, it is likely not as effective as handwashing, since we are more likely to touch things than put our mouths near them.

I’m not exactly sure what your trying to ask, but if it’s how an organelle is similar to a body system or a part a nucleus is like a in function. but i don’t fully understand what you’re trying to ask