Across
- 3. crude oil is refined to make ____________.
- 4. ______ soil is good for growing plants.
- 6. All life on earth depends on ________ for survival.
- 7. ______ is the top layer of the earth's crust.
- 9. Rocks such as marble, granite and sandstone are used to make ____________.
- 10. Carbon dioxide is used by _______ to prepare food.
Down
- 1. __________ such as coal and petroleum are natural resources.
- 2. ___allow heat and electricity to pass through them.
- 5. Metals are extracted from __________.
- 8. ______is necessary for respiration and combustion.