Across
- 2. The upper level of groundwater at a place is called _____.
- 4. Water that flows over the land after precipitation is called _______ water.
- 5. Resources that can finish soon if not used wisely are called _____ resources.
Down
- 1. The process by which exchange of gases occurs in simpler, single-celled organisms is called ______.
- 3. The two tubes in which trachea divides is called ______.