Read this: Copper is biostatic, meaning bacteria will not grow on it. For this reason it has long been used to line parts of ships to protect against barnacles and mussels. It was originally used pure, but has since been superseded by Muntz metal. Similarly, as discussed in copper alloys in aquaculture, copper alloys have become important netting materials in the aquaculture industry because they are antimicrobial and prevent biofouling, even in extreme conditions and have strong structural and corrosion-resistant properties in marine environments.

What word means that bacteria constantly grows on a substrate?
What is the answer? (If it cannot be answered, return "unanswerable")
unanswerable