Hydrothermal vents are often rich in metals, such as copper, and also host dense populations of marine organisms. which of the following is clearly a non-renewable resource: copper, crabs, and/or mussels?

The answer is copper. Nonrenewable resources are those that cannot be readily/naturally replaced at rates that match those of consumption (an aspect that allow renewable resources to be sustainable). Copper are made deep in earth at very slow rates hence do not readily renew themselves. Organisms, on the other hand die, and are naturally replaced by offspring.