Solve these clues to fill the grid.
- The state of being clean and conducive to health
- 2 Across
- A low area where the land is saturated with water (plural)
- 3 Across
- The state of being clear of trees
- 8 Across
- Waste matter that contaminates the water or air or soil (plural)
- 9 Across
- Frequent and watery bowel movements
- 10 Across
- An organization of independent states formed in 1945 to promote international peace and security
- 11 Across
- The maintenance of a certain quantities unchanged during chemical reactions or physical
- 1 Down
- Layer of air around the Earth
- 4 Down
- A heavy odorless colorless gas formed during respiration and by the decomposition of organic
- 5 Down
- An increase in the average temperature of the earth's atmosphere
- 6 Down
- Available source of wealth (plural)
- 7 Down