Which set of conditions allows liquid water to exist on earth? a. strong magnetic fields and lunar tides b. comet crashes and volcanic eruptions c. moderate temperatures and strong gravity d. hydrogen bonds and moderate distance from the sun

C. Moderate temperatures and gravity helps liquid water to exist on Earth.

For liquid water to exist on the planet Earth, right atmospheric pressure, temperatures, and gravity is essential to maintain everything under control.

Gravitational force of attraction exists on Earth which holds anything towards the core of the planet. Heavy temperatures cause greenhouse effect but moderate causes things to be in proper place. Very less temperatures solidify the liquids. So, be it liquid water or land, gravitation and moderate temperatures have the capacity to helps liquid water to exist on Earth.