What do most cars, factories, and power plants rely on to operate?

They rely on fossil fuels to operate.
Fossil fuels are there energy source and most of these factories and power plants burns fossil fuel in order to obtain a usable energy form. However, burning of fossil fuel is not environmentally friendly as it produces carbon dioxide that can trap heat inside the atmosphere leading to global warming.

Interacting group of various species in a common location. for example, a forest of trees and undergrowth plants, inhabited by animals and rooted in soil containing bacteria and fungi, constitutes a biological community.