Which energy source is commonly associated with generating electricity from tidal movements?

• A. Biomass
• B. Geothermal
• C. Water
• D. Solar

Answer: (C)

This question tests recognizing that tidal electricity comes from the movement of sea water. Tidal energy uses the flow and height differences of tides to turn turbines and generate power, either with turbines placed in fast-moving tidal currents or with a dam that allows controlled water flow to drive turbines. The energy source here is water, specifically the kinetic and potential energy of moving ocean water.

Biomass uses organic matter for energy, geothermal relies on heat from underground, and solar uses sunlight. These sources are not tied to tidal movements, which is why water is the best answer.