Earth Day

6. a measure of the amount of greenhouse gas produced in our day-to-day lives through burning fossil fuels for electricity, heating and transportation, etc.
7. to consume, spend, or employ uselessly or without adequate return; use to no avail or profit; squander
8. the degree to which the ambient air is pollution-free, assessed by measuring a number of indicators of pollution
9. a wildlife species that is facing imminent extirpation or extinction
12. the planet third in order from the sun, having an equatorial diameter of 7926 miles
13. the elements of the natural world, as mountains, trees, animals, or rivers
14. the introduction of harmful substances or products into the environment
15. the composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years

1. the quality of not being harmful to the environment or depleting natural resources, and thereby supporting long-term ecological balance
2. an increase in the earth's average atmospheric temperature that causes corresponding changes in climate and that may result from the greenhouse effect
3. general term for buried combustible geologic deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the Earth’s crust over a period of hundreds of millions of years
4. to treat or process (used or waste materials) so as to make suitable for reuse
5. gases in the Earth’s atmosphere that trap heat
10. the power or ability to return to the original form, position, etc., after being bent, compressed, or stretched; elasticity
11. a mixture of various decaying organic substances, as dead leaves or manure, used for fertilizing soil