Alexis and candace were testing different surfaces to see which one had the least friction. they predicted that the marble, seen above, would travel fastest down the ramp when the surface covering had the least friction. alexis and candace used rocks, plywood, and velcro to cover the ramp. they let the marble go, not pushing it, but letting gravity pull the marble to the bottom of the ramp.

what is/are the responding variable(s) in the experiment?

a) the different types of ramp coverings

b) how fast the marble moved down the ramp

c) ramp height, the marble, and using gravity

d) pushing or not pushing the marble down the ramp

correct answer is option a.

tropopause, stratopause and mesopause have all in common aspect that is point of maximum temperature in its layer of the atmosphere. all layers of atmosphere observe abrupt change in temperature. tropopause is the boundary between troposphere and stratosphere. stratopause is the boundary between stratosphere and mesosphere. mesopause is the boundary between mesosphere and thermosphere. these all boundaries are ranges between altitude of 0 to 80 km.

the answer is lactic acid from anaerobic respiration. the acid in lactic acid is what creates sore and burning muscles. if you think about how acid burns that will give you a clue for questions like this.

bradykinin is a physiologically and pharmacologically active peptide of the kinin group of proteins, consisting of nine amino acids.