This is an alternate content page containing a Crossword Activity. It has opened in a new window.
Here are the clues. Preceding each clue is the number of letters in the answer.

Clue 1: 4 letters. The smallest unit of matter.
Clue 2: 10 letters. All the organisms of the same species.
Clue 3: 9 letters. All the living and nonliving things in an area.
Clue 4: 8 letters. A cluster of atoms bonded together.
Clue 5: 9 letters. All the living things in an area.
Clue 6: 9 letters. All of the environments on Earth that support life.