The ocean covers ________ percentage of Earth’s surface.

The correct answer is: C. 71%

The ocean covers 71% of Earth’s surface. It is the largest habitat on Earth, and it is home to a vast array of life. The ocean plays a vital role in regulating the Earth’s climate, and it is a major source of food and resources for humans.

Option A is incorrect because the ocean covers 71% of Earth’s surface, not 51%.

Option B is incorrect because the ocean covers 71% of Earth’s surface, not 61%.

Option D is incorrect because the ocean covers 71% of Earth’s surface, not 91%.