Which part of the Earth system contains most of the planet's mass?

Geosphere of the Earth system contains most of the planet's mass.

Explanation:

One of the most important is the Carbon Cycle since all of the organisms on Earth are carbon-based life forms. includes all water on the surface of the earth oceans, lakes, rivers, aquifers, and ice. 70% of the earth's surface is covered with water.

there is none because earth is stationary and flat.