Answer:
Run off of animal/plant waste
Explanation:
The run off of animal/plant waste occurs in 3 layers:
upper layer: the terrestrial chamber, the decomposition chamber, and the aquatic chamber.
The terrestrial layer represents the land habitat including plants and insects whereby waste are moved into the
The decomposition layer much like a compost pile where it decomposes and then move into
The aquatic layer much like a mini freshwater habitat for aquatic plants and even small fish, it serves as food sources for them
Hydrogen and hydroxide ions
Do further research into how the result was obtained and look to see if there was anything remotely different in the trial.
This is called Natural Selection. Essentially, "the strong survive".