Final answer:
A biofilm provides a physical barrier to antibiotics, shielding the target cells from exposure. The extracellular matrix of a biofilm prevents antibiotics from reaching the cells, making them more resistant than isolated cells or colonies. Nutrient limitations within a biofilm can also increase drug resistance.
Step-by-step explanation:
One characteristic of a biofilm is that it provides a physical barrier to antibiotics, shielding the target cells from exposure. The extracellular matrix of a biofilm prevents antibiotics from reaching the cells, making them more resistant than isolated cells or colonies. Additionally, nutrient limitations deep within a biofilm can slow metabolism and increase drug resistance, adding another level of resistance.