Final answer:
The subject of this question is Biology. The student is asking about a phenomenon that flows near the top of the ocean but can reach depths of several hundred meters. This phenomenon is likely ocean currents or tides.
Step-by-step explanation:
The subject of this question is Biology.
The ocean is categorized into different zones based on depth. The photic zone extends from the surface to 200m, where light can penetrate and photosynthesis can occur. Beyond 200m, the ocean enters the aphotic zone, where light cannot penetrate. The student is asking about a phenomenon that flows near the top of the ocean but can reach depths of several hundred meters. This phenomenon is likely ocean currents or tides, which are driven by factors such as temperature, wind, and the rotation of the Earth.