The dependent variable is the part of the experiment that depends on the other part, the independent part. The dependent variable would be the plant because it's growth depends on the light wavelength.
A catalyst works by providing an alternative reaction pathway to the reaction product. a catalyst speeds up a reaction.
Since the cell is hypotonic compared to the solution surrounding it which is hypertonic, the water will move out of the cell in an effort to reach equilibrium between the two.
