Although coal and petroleum are produced by degradation of bio-mass, yet we need to conserve them. Why?

Although coal and petroleum are produced by degradation of biomass, yet we need to conserve them. Why?

Although coal and petroleum are produced by degradation of biomass, yet we need to conserve them. Why?

Although coal and petroleum are produced by degradation of biomass, we need to conserve them. Why? Mention two reasons.