Final answer:
Evaporites and coquina can be classified as either chemical or biochemical sedimentary rocks. Chert is generally chemical, while banded iron formations signify early Earth conditions due to the presence of dissolved oxygen.
Step-by-step explanation:
The rocks that can be chemical or biochemical are evaporites and coquina. Evaporites form when water that contains dissolved minerals such as salt evaporates and leaves behind solid mineral deposits. These are classified as chemical sedimentary rocks. On the other hand, coquina is a type of limestone composed primarily of shell fragments; its formation is the result of biological processes leading to the chemical precipitation of calcium carbonate, making it a biochemical sedimentary rock.
Chert, while often formed from the accumulation of silica from the bodies of microscopic organisms, can also form inorganically, making it fall under the chemical category. The banded iron formation is indicative of early Earth conditions, particularly the presence of dissolved oxygen, which accounts for the alternating bands of iron-rich and iron-poor layers in these rocks.