Which of these factors best explains why liquid water exists on earth?

a. weak salinity of earth's oceans

b. earth's strong gravity

c. presence of living things on earth

d. freezing temperatures at earth's poles

b. earth's strong gravity

Explanation:

On our planet, during the degassing process, the Earth's core was still hot, and a large amount of water in the form of vapor was expelled into the crust. The volcanoes expelled hydrogen gas and water vapor. This process has created our atmosphere. As the temperature went down, there was condensation of the gas, which gave rise to clouds and the consequent occurrence of precipitation, which returned to Earth due to the force of gravity. The water in liquid state was suspended on the surface of the atmosphere, giving origin to the primitive oceans.

With this we can conclude that what made it possible for the planet earth to have liquid water was the presence of a strong gravitational force.