The structures that help some bacteria to attach to rocks or host tissues are
Fimbriae
The correct option is C.
Explanation of the correct option:
Explanation of the incorrect options:
Option A:
A holdfast is a root-like structure that secures aquatic sessile creatures to the substrate, including sponges, benthic cnidarians, stalked crinoids, and other sessile algae.
Option B:
Option D:
Final answer:
The structures that help some bacteria to attach to rocks and /or host tissues are fimbriae.