Hazards and Estimates of Fossil Fuels

Q. “We should practice the habit of conserving energy”.
Which of the following statements is related to the above comment?

1. Increased use of fossil fuels is depleting their sources far too fast.
2. All the energy used today is obtained from non-renewable sources.
3. Large areas of forest have been cut down to obtain fire wood.
4. Sunlight is gradually becoming dimmer.