Which of the following statements about water on Earth is true? a.)
Water covers approximately 90% of the Earth’s surface.

b.)
3% of Earth’s water is in the oceans.

c.)
Approximately 7% of freshwater is found in glaciers.

d.)
Only about 1% of freshwater is easily available for human use.

Select the correct answer. what was edwin hubble's contribution to the field of astronomy? a. he discovered variable stars. b. he proved that the heliocentric model accurately described our solar system. c. he found a relationship between the period luminosity and distance of stars. d. he proved that the universe is finite. e. he discovered that the universe was expanding.