Solution:
Concept- Energy is used to power the devices we use for heat and light in our homes, for transportation, and to make all kinds of products. The primary use of these various energy sources is the production of electricity.There are 9 main different energy sources:-Solar energy, Wind energy, Geothermal energy, Hydrogen energy, Tidal energy, Wave energy and water energy.
Now, the primary source of energy should be the one which cannot be replaced by any other source. Thus, the Sun is the primary source, because the complete energy on our planet is given by the sun in the form of radiation. When these radiations hit the Earth, they hit the surface of the molecules. These molecules absorb some of their energy. This reduces their energy and as a result the radiation cannot return back to space. They therefore remain in the atmosphere and thereby heat it, which is a basic necessity.
Hence, the correct option is (4).
