Which of the following is a nonrenewable resource?
AWind energy
BSolar energy
CNatural gas
DTimber from managed forests
Natural gas is a fossil fuel that formed from ancient organic material over millions of years. Once extracted and burned, it cannot be replaced on any human timescale. Wind and solar energy are continuously supplied by nature. Timber from managed forests is renewable if trees are replanted and given time to grow.
Question 2 Short Answer
Why are fossil fuels classified as nonrenewable even though they formed from natural processes?
Think about your answer, then reveal below.
Model answer: Fossil fuels formed from the remains of ancient organisms buried and transformed over millions of years under specific heat and pressure conditions. While the process is natural, it takes far too long (millions of years) to produce new fossil fuels on any human timescale. We are using them thousands of times faster than nature creates them, making them effectively nonrenewable for our purposes.
This is the key concept — 'renewable' and 'nonrenewable' are defined relative to human timescales. A resource is nonrenewable if we cannot replace it within a human lifetime or even within many generations. Fossil fuels are a one-time inheritance from Earth's geological past.
Question 3 True / False
Renewable resources can seldom be depleted or used up.
TTrue
FFalse
Answer: False
Renewable resources can be depleted if they are consumed faster than they regenerate. Overfishing can collapse fish populations. Clear-cutting forests faster than they can regrow leads to deforestation. Over-pumping groundwater faster than rainfall recharges it can drain aquifers. 'Renewable' means replaceable, not inexhaustible — sustainable management is still required.