Answer 1) : Hydrosphere.
Explanation : The largest sphere on the planet is hydrosphere, which is the combined mass of water found on a planet, available under, and above the surface of a planet, minor planet or natural satellite. It has been estimated that there are 1,386 million cubic kilometers of water on Earth. So, this is the largest sphere on a planet if you are traveling on Earth.
Answer 2) The other parts of the sphere are geosphere, atmosphere and biosphere.
Explanation : Geosphere - This sphere includes all the stuff that make up the crust and the core of the earth. It includes everything natural and lifeless that make up the surface of the earth. Examples are all the rocks and sand particles from dry land to those found at the bottom of the oceans.
Atmosphere - The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity.
Biosphere - It is also known as the ecosphere, is the worldwide sum of all ecosystems. It can also be termed the zone of life on Earth, a closed system, and largely self-regulating.
