An oligopoly is: a.
fifteen to eighteen firms producing 90 percent of the output.

b.
one firm producing 95 percent of the output

c.
ten to fifteen firms producing 40 percent to 50 percent of the output.

d.
a few firms producing the majority of the output.

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?