What is the main source of energy that drives the earth's systems?

Sun is the main source of energy that drives the earth's systems

Explanation:

Sun radiates huge amount of energy but only limited amount of energy reaches the earth which is enough to light the days and balance the ecosystem and climate system.

With time earth’s system is constantly changing whether it be climatic, geographic, ecological etc. These changes are always associate with the flow of energy in the solar energy. It drives many processes such as wind currents, hydrologic cycle and the climate system. Sun warms the planet and makes life on earth possible, helps in photosynthesis, atmospheric circulation, evaporation etc. . It is also called the heat engine of the earth.

it takes hundreds of years to become stable.

if you have another question lmk.

the real answer is b. scintillation counter