Aclass is designing an experiment about duckweed growing conditions. the hypothesis for the duckweed experiment is, “if duckweed is grown at ph 5, then it will grow at the same rate as when grown at ph 7, or normal ph, because it can tolerate mildly acidic environments.” identify the control group in this experiment.

Which explanation describes the forces involved for a person to walk down the sidewalk? a. the person's feet push backward on the sidewalk; the sidewalk pushes backward on the person. b. the person's feet push forward on the sidewalk; the sidewalk does not push on the person. c. the person's feet push backward on the sidewalk; the sidewalk pushes forward on the person. d. the person's feet push forward on the sidewalk; the sidewalk pushes forward on the person.

Decreased sensitivity to an unchanging stimulus is known as

In the united states, tornadoes generally occur because of the freezing of ocean water underwater earthquakes meeting of cool and warm air masses shifting of warm and cool ocean currents