Looking from space, you can see that Earth is a “blue” planet. That’s because of the ocean. The ocean covers about 70 percent of Earth’s surface (表面). Around 700,000 to 1 million species live in it. That’s far more species than we have on land! However, we have only explored a small part of the ocean. We have found just one-third of the ocean’s species. It’s time to dive into the deep and find out more of its secrets!