Question

which personal behavior has not been proven to keep one healthy?
avoiding tobacco
washing hands often
doing self - examinations
drinking caffeinated coffee

Explanation:

• Avoiding tobacco reduces risks of many diseases.
• Washing hands often helps prevent infections.
• Self - examinations can detect health issues early.
• While some studies suggest limited benefits of coffee in moderation, it is not a behavior proven to "keep one healthy" in the same fundamental way as the others. For example, it doesn't directly prevent major diseases or infections like the first three behaviors.

Answer:

drinking caffeinated coffee