The document defines supply as the quantity of a commodity offered for sale at a given price during a specific time period. It states that the law of supply is that, other things remaining the same, quantity supplied rises with price and falls with lower price. The supply curve slopes upward due to factors like diminishing marginal productivity and profit maximization goals of producers. The determinants of supply include price of the commodity, price of related goods, technology, costs, and government policy. The document discusses individual and market supply schedules and curves, and how movements along and shifts of the supply curve represent changes in quantity supplied and changes in supply, respectively.