Can I get help with this science problem

Astudent conducts an experiment to determine how the amount of water given to a plant affects it growth what is the dependent variable for this experiment

Which statement describe events that occur during interphase?

Which of the following is likely not involved in this example of ecological succession? a) the rotting remains of plants add to the fertility of the soil. b)the soil becomes so fertile that eel grass is replaced by other plant species. c) the roots from plants stabilize the sediment, keeping it in place. d) the concentration of salt becomes so high that all plant life is destroyed.