Please answer the following question: Researchers in over 80 nations are taking part in a project to conduct a decade-long census  of sea life. Scientists presented some of their findings at a recent conference as the project neared its completion. In deep icy waters under Antarctica, scientists found bulbous tunicates, an underground animal, and many newly-discovered creatures believed to be related to starfish   and other marine creatures. Elsewhere in the world's oceans, they have recently discovered many kinds of underwater life forms new to science. It is all part of a research effort called the Census of Marine Life. "There are about 2,000 scientists worldwide involved," said Bob Gagosian, President, CEO of the Consortium for Ocean Leadership. Gagosian helps manage the project. "Everywhere they've gone they've found new things," he says. "The ocean basically is unexplored from the point of view of marine living things." Researchers have placed small markers on hundreds of fish and marine animals to track by satellite their migration routes and to discover places where sea life gathers. According to Ron O'Dor, a senior scientist with the Census of Marine Life, knowledge of life on the ocean floor is especially limited. "90% of all the information we have is from the top hundred meters of the ocean," O'Dor states. And he says the sea floor is, on average, at a depth of 4, 000 meters. And so, as some machines dive far below what people have previously seen, scientists are discovering new species of plants, animals and living things. Since the census project began, more than 5,300 new marine animals have been found. Ocean researchers say they hope to catalogue 230,000 species during the census --which some say is only a small part of all the creatures living in the sea. From what Ron O'Dor says, we can conclude that  _  . A) human beings only know a little about marine life B) the oceans don't need to be further explored C) he considers exploring the ocean a dangerous thing D) the marine creatures mainly live on the top of the ocean
A:
A