Which of the following describe how biofilms work to be resistant to many antibiotics?
1) Biofilms produce a protective matrix that prevents antibiotics from reaching the bacteria.
2) Biofilms can alter their gene expression to become resistant to antibiotics.
3) Biofilms can form physical barriers that prevent antibiotics from reaching the bacteria.
4) Biofilms can pump out antibiotics using efflux pumps.
5) All of the above
