How do organisms like coral and shellfish use carbon to make their shell?

As carbon dioxide from the burning of fossil fuels has accumulated in the atmosphere, some of it has been absorbed by the ocean. As the gas dissolves in the water, it forms a weak acid (the same kind that's in bubbly soft drinks), causing the ocean itself to become gradually more acidic.
As ocean water becomes more acidic, it also lowers the amount of calcium carbonate available to aquatic animals that use the mineral to build shells or skeletons, such as corals. These organisms can be important links in the marine food chain.

Hope this helps:)

Heyhonestly, probably not. humans have always had a tendency to waste things. whether it's food, cosmetic, infrastructure, or our abandoned constructions,the landscape is littered with the refuseof man. archaeology wouldn't be a developed discipline if humans didn't leave things behind. in a way it makes us human

hope it mark me as brainlieast.

Confused on question what should we be answering