An ocean, a forest, and a grassy meadow are each examples of a complete ecosystem. Complete ecosystems contain only
A: living and nonliving things.

Which SI unit would be most appropriate for recording the length of a typical classroom?
A: meter

Why can a small fire be put out by placing a heavy blanket over it?
A: This keeps oxygen from reaching the fire.

Which environmental stimulus causes leaves on certain trees to change color in autumn?
A:
changes to amount of light