A biome is a large naturally occurring community of flora (plants) and fauna (animals) occupying a major habitat (home or environment).

An ecosystem is a biological community of interacting organisms and their physical environment. This includes both the biotic (living) and abiotic (non-living).

If the ovum fails to become fertilized, the lining of the uterus sloughs off during menstruation. From puberty to menopause, this cycle of menstruation repeats monthly (except during pregnancy).

Primary consumers (herbivores) subsist on producers like plants and fungus. Examples are grasshoppers, cows, and plankton.

Food is mixed with gastric acid and pepsin in the stomach to help break down protein.