Final answer:
Biofilms are particularly resistant to antibiotics and immune responses due to their protective extracellular matrix and the potentially dormant state of some of their bacterial cells, making them much harder to eliminate than planktonic bacteria.
Step-by-step explanation:
The statement about biofilms that is correct is that c) Biofilms are resistant to antibiotics and immune responses. Biofilms are complex communities of microorganisms that adhere to surfaces and are embedded in a self-produced matrix of extracellular polymeric substances. They represent a significant problem in both healthcare settings and the environment because they shield bacteria from antibiotics and the host immune system, making them much more difficult to eradicate than free-floating bacteria.
This resilience is due to several factors. For one, biofilm's extracellular matrix can prevent antibiotics from reaching bacteria at effective concentrations. Additionally, some bacteria in biofilms enter a dormant state, which makes them less susceptible to drugs that target actively growing cells. Moreover, the close proximity of bacteria within a biofilm facilitates the transfer of genetic material, including genes that confer resistance to antibiotics.
The other statements are incorrect because biofilms can be formed by non-pathogenic bacteria, they include components other than living bacterial cells (such as extracellular matrices), and they are typically not easily removed by normal cleaning processes.