Why are fossil fuels considered finite?

A finite resource is something that can only be consumed once without possibility of being recycled for re-use. Because fossil fuels are burned, they cannot be reused and are therefore a finite resource.

Explanation:

they each offer a fresh glut of resources to the organisms that can arrive and exploit them. as individuals and new species continue to appear, they actively and passively alter the environment. competition for shared resources increases, local abiotic and biotic conditions shift, and the relative abundances of species change accordingly. the process is called ecological succession, and it is one of the earliest and most well-known concepts in ecology.