Across
- 2. worldwide system of computer networks
- 4. material such as coal, gas, or oil that is burned to produce heat or power.
- 6. the study of living organisms
Down
- 1. liquid that is made up of organic molecules
- 3. the strength and vitality required for sustained physical or mental activity.
- 5. all of space and time and their contents
- 7. substance that flows freely but is of constant volume, having a consistency like that of water or oil.