Which term describes the phenomenon of the regular rise and fall of the ocean's surface?

• A. The tides
• B. High tide
• C. Neap tide
• D. Spring tide

Answer: (A)

The regular rise and fall of the ocean’s surface is called tides. This happens because the gravitational pull of the Moon—and to a lesser extent the Sun—creates bulges in Earth's oceans. As Earth rotates, different areas move into and out of those bulges, so water levels rise to high tide and fall to low tide in a repeating cycle. The Sun’s gravity can strengthen or weaken this effect depending on the alignment with the Moon, leading to variations like spring tides (larger difference) and neap tides (smaller difference). The other terms refer to specific moments or types within the tidal cycle—high tide is simply a peak in water level, while neap and spring tides describe the strength of the tides—not the overall phenomenon.