Prime objective of this lecture is to present on Sun: Energy Path. Sun path refers to the apparent significant seasonal-and-hourly positional changes of the sun as the Earth rotates, and orbits around the sun. In this lecture briefly describe on Photosynthesis, Energy Pyramid and Fossil Fuels. Fossil Fuels are made of thousands of years old dead plants and animals. They are buried under tons of Earth and the energy contained in the plants and animals is converted to oil.