a. State how each of the following factors affects the materials balance model: 

(i) Population growth; 

(ii) Income growth; 

(iii) Increased consumer recycling actions; 

(iv) Increased industrial recycling; 

(v) Increased use of pollution prevention technologies.

b. Assume that stringent pollution controls are placed on the flow of residuals released into the atmosphere. According to the materials balance model, what does this imply about the residual flows to the other environmental media and/or the flow of inputs into the economy?