Which term describes substances that can be absorbed by organisms?

The correct term that describes substances that can be absorbed by organisms is bioavailable. Bioavailability refers to the extent and rate at which the active ingredient or active moiety is absorbed and becomes available at the site of action. In the context of water quality, substances in water can be bioavailable if they can be taken up by living organisms, such as plants and animals. This concept is crucial for understanding how different pollutants or nutrients impact ecosystems, as only bioavailable substances can have a biological effect on the organisms consuming them.

The other terms provide a different context. Biodegradable refers to substances that can be broken down by biological processes, typically by microorganisms. Biochemical pertains to the chemical processes and substances that occur within living organisms, but it does not specifically address absorption. Biotic describes living components of an ecosystem, such as plants, animals, and microorganisms, rather than the substances they can absorb. Thus, bioavailable is the most precise term for substances that can be taken up and utilized by organisms.