Process:  - Human industry produces chemical compounds - Chemical compounds rise into the air - Chemical compounds mix with elements in clouds - The affected rain falls to the earth - The affected rain can harm natural and man-made objects because of its acidic content.  Perturbation hypothesis: suppose customers are not buying the products happens, how will it affect less compounds rise in the air.  Does the supposed perturbation have an effect (direct or indirect) on the process?
Answer:
yes