Crossword Puzzle

123456789
Across
  1. 3. Water located beneath the earth's surface in soil and rock layers. (11 letters)
  2. 4. Seasonal movement of animals from one region to another. (9 letters)
  3. 6. Organism that lives on or in another organism and benefits at the host's expense. (8 letters)
  4. 7. Study of the interactions between organisms and their environment. (7 letters)
  5. 8. Total mass of organisms in a given area. (7 letters)
  6. 9. Contamination of the environment with harmful substances. (9 letters)
Down
  1. 1. Animal that primarily feeds on plants. (9 letters)
  2. 2. Animal that primarily feeds on meat. (9 letters)
  3. 5. Chemical substances used to kill or control pests. (10 letters)
  4. 6. Animal that hunts and feeds on other animals. (8 letters)