Answer: Antibacterial.
Bacteria can be described as a small part or member of a broad group of unicellular tiny microorganisms which have numerous cell walls in them but lacks organelles and an organized and proper nucleus, including some that can cause major disease. On the other hand, antibacterial refers to an antibiotic or antiseptic which is a type of antimicrobial agent mainly used to prevent bacteria; it might kill them in many cases. Explanation:
1. Bacteria are sort of tiny microscopic living organisms, usually found in one-celled everywhere.
2. They can be sometimes very dangerous, when they form infection in people, or can be sometimes beneficial, such as in the procedure of fermentation in wine, etc., and also in decomposition.