The coral fossil would be a better estimate of past water depth. This is because most corals inhabit shallow water reefs, less than 150 feet deep. In contrast, pelagic fish may inhabit any open water (pelagic) part of the ocean, with depths ranging anywhere from a couple of hundred feet deep to miles in depth.
Energy convention: Convection is the motion of a fluid driven by temperature differences across that fluid. When a fluid is heated, the region in closest contact with the heat source becomes less dense due to increased kinetic energy in the particles. Convection is one of the fundamental ways that heat is transferred
Protoplanets are bodies or celestial objects which have the same size as the moon or a bit bigger. These bodies develop to eventually become planets. Therefore, the answer to this item is most likely letter D. outer planets.