Scientists theorized that all ecosystems need sunlight as an energy source. What has been discovered on the ocean floor that has challenged this theory?
A
ecosystems based around hydrothermal vents that rely on the vents' heat and chemicals for energy
B) ecosystems that get their energy from nuclear energy sources found on the ocean floor
ecosystems that rely on energy from bottom-feeding fish
D ecosystems that do not need any energy source

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.