Which step would be most appropriate for an investigation that tests how ocean water absorbs heat over time?

To test how ocean water absorbs heat over time, compare how water changes when exposed to a heat source versus when it is not. Placing one container in the sun and another in the shade provides that comparison; the water temperatures can be measured over time. The other choices test melting, dissolving, or acidity rather than heat absorption.

AI-written and checked against the verified answer.