Question

why is earth often referred to as the blue planet?
○ most people like blue.
○ the sky is blue.
○ when viewed from space, the biosphere always looks blue.
○ the hydrosphere looks blue and covers three - fourths of the earths surface.

Explanation:

The Earth is called the blue planet because about 71% (three - fourths) of its surface is covered by water in the hydrosphere, which appears blue from space. The blue color is due to the way water absorbs and reflects light.

Answer:

The hydrosphere looks blue and covers three - fourths of the Earth's surface.