A、10 years. B、20 years. C、30 years. D、50 years. AHow long have scientists been exploring the world’s oceans?

Scientists are gearing up for one of the most ambitious international research programs ever attempted: a decade-long exploration of the world’s oceans to unlock some of the most closely held secrets of the creatures of the deep. Using sophisticated technology that was not available even five years ago, the scientists will rely primarily on the animals they want to study to collect the data needed to complete the "Census of Marine Life". Creatures ranging from blue whales to turtles will be fitted with satellite tracking devices that will record their every movement. The project, involving scores of institutions around the globe, is expected to cost upwards of $1 billion, and it will take at least 10 years. The scientists hope the research will tell us much more about a region of the earth we understand so poorly. That area, incidentally, covers 70 percent of the globe.