AP BIOLOGY

Detailed explanation-1: -About 71 percent of the Earth’s surface is water-covered, and the oceans hold about 96.5 percent of all Earth’s water. Water also exists in the air as water vapor, in rivers and lakes, in icecaps and glaciers, in the ground as soil moisture and in aquifers, and even in you and your dog.

Detailed explanation-2: -Depending on how they’re defined, grasslands account for between 20 and 40 percent of the world’s land area. They are generally open and fairly flat, and they exist on every continent except Antarctica, which makes them vulnerable to pressure from human populations.

Detailed explanation-3: -There are over 510 million square kilometers of area on the surface of Earth, but less than 30% of this is covered by land. The rest is water, in the form of vast oceans.

Detailed explanation-4: -The ocean covers more than 70 percent of the surface of our planet. It’s hard to imagine, but about 97 percent of the Earth’s water can be found in our ocean. Of the tiny percentage that’s not in the ocean, about two percent is frozen up in glaciers and ice caps.