题目

If you’re looking at diving for the first time in Papua New Guinea, believe everything you have read about our world-class waters.Called the “underwater photographer’s paradise”, we’ve got many international awards for underwater photography taken here. In our oceans you'll see up to twice as many marine species as the waters of the Red Sea and up to five times as many as the Caribbean. Our waters enjoy a huge diversity of dive sites, including reefs, coral walls, seagrass beds, and wreck dive sites (ships, aircraft and submarines!).Must seeDive down to a fully complete Japanese figh质量和体积都相等的三个空心球，分别由铝、铁、铜制成，已知ρ铝＜ρ铁＜ρ铜，由此可得三个球空心部分体积的关系是A．铜球的最大 B．铁球的最大 C．铝球的最大 D．一样大