Ecology Crossword Puzzle

1234567
Across
  1. 4. is electricity made by moving water
  2. 5. tools, machines, or inventions people use to solve problems or do work.
  3. 7. the study of relationships between living things and their environment
Down
  1. 1. is a condition in which a kind of plant or animal dies out completely
  2. 2. are microscopic organisms
  3. 3. held firmly in place
  4. 6. decompose on the forest floor after they die