Answer:
Alcohol
Explanation: Alcohol in moderation isn't bad but when one starts drinking heavily it can be detrimental to one's health
I think the answer might be Euchromatin. Chromatin exist in two forms. One being Euchromatin which is less condensed and can be transcribed.
BIODEGRADABLE. Is what they are called
You have a lot of control over it. You can choose to be active, you choose what types of foods you eat. You can also control if you smoke, or drink. You basically have around 80%-90% of control. If you do the right things I think It will lessen your chances of having the disease.
Hope this helps!