Which statement best illustrates a biotic or an abiotic factor that is often found in a city park?
o decaying leaves are an abiotic factor because they are not living.
o rocks are an abiotic factor because they have never been alive.
o water in ponds is a biotic factor, because it provides a habitat for living things.
o oxygen is a biotic factor, because it is required for life and found in all living things.

Asample of digestive juice was removed from the stomach of a pig. the juice was placed in a test tube along with some grains of wheat. a second test tube was set up containing an equal number of wheat grains, with distilled water rather than digestive juice. the test tubes were kept for 8 hours at 40 degrees c. after 8 hours, the grains inside the digestive juice had broken into tiny particles. the grains of wheat, in the water, were wet but otherwise unchanged. what is the control group?