Which of the following is not an agent of mechanical weathering?

Match 40 ! economics 1. equilibrum 2.disequilibrium 3. excess demand 4. excess supply 5.price ceiling 6. price floor a. when quantity supplied exceeds quantity demanded b. this occurs when quantity supplied in not equal to quantity demanded in a market c.the point of balance between price and quantity d. the maximum price that can be legally charged for a good e. when quantity demanded is more than wuantity supplied f.the minimum price that can be legally chsrged for a good or service