A
1 and 2 only
B
2 and 3 only
C
1 and 3 only
D
1, 2 and 3
Correct answer: (d) 1, 2 and 3
Explanation
- A
1 and 2 only
1 and 2 only. Antibiotic tolerance/resistance of biofilms is also true.
- B
2 and 3 only
2 and 3 only. Implants grow biofilms too.
- C
1 and 3 only
1 and 3 only. Food-contact surfaces are a standard biofilm site.
- D
1, 2 and 3
All three. Implants, food plant surfaces, and hard-to-treat biofilm resistance.
Summary. Official key is (d) all three. Biofilms colonise implants and food-processing surfaces and are markedly less susceptible to antibiotics than planktonic cells.