The graph shows the change in concentration of one of the species in the reaction A + B + C→D.

If the graph indicates the reaction rate, then the concentration of which species is plotted?

A

B

C

D

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.