Final answer:
Bioherms are geological formations made up of algae, corals, and shells, all contributing to their complex structure with materials like calcium carbonate and silica dioxide.
Step-by-step explanation:
Bioherms are geological structures formed by the skeletal remains and waste products of living organisms. The main components that make up bioherms are algae, corals, and shells. Specifically, these formations can be built from large colonial organisms such as corals, which secrete calcium carbonate skeletons. These coral structures, usually found in shallow tropical water, develop into coral reefs, providing essential habitats for various marine life forms. Algae, including types such as coccolithophores and diatoms, contribute to bioherms by producing calcium carbonate plates or silica dioxide cell walls, respectively. Shell remains from various marine organisms also accumulate and can become part of a bioherm structure.
Considering the diverse materials that comprise bioherms, they are indeed made of algae, corals, and shells, thus the correct answer is (d) All of the above.