Imagine you are in a laboratory. you are exploring
the following reaction: a+b - c
when the product c is created, bubbles form.
when 10ml of a is added to 10ml of b, the
reaction takes twenty seconds. your teacher gives
you three unknown substances (x, y, and z), one
of which is a catalyst for the reaction.
design an experiment to test substances x, y, and
z to determine which one is a catalyst for the
reaction.

i believe it would cause an increase of percipitation, though i could be wrong. so i would say b is the answer.

1. the energy lost to disorder metabolism     -entropy

2. related to or possessing motion potential     -kinetic

3. all of the chemical reactions in an organism required for maintenance of the processes of life entropy     -metabolism

4. possible; ability to go into action or perform work kinetic     -potential

5. the study of energy and its transformations thermodynamics     -thermodynamics