1.5 Supply
Supply shows the quantity sellers offer at each price; it slopes up by the law of supply and shifts with input costs, technology, taxes, and expectations.
The law of supply says price and quantity supplied move together, so the supply curve slopes upward: higher prices make additional production profitable even as marginal costs rise. Each point answers how much sellers will offer at that price, holding everything else constant.
Supply shifts when a non-price determinant changes: input (resource) costs, technology, taxes and subsidies, producer expectations, or the number of sellers. Cheaper inputs or better technology shift supply right; a per-unit tax or costlier inputs shift it left.
As with demand, the good's own price never shifts its supply curve — it causes a movement along it, a change in quantity supplied. Say 'supply increased' only when the whole curve moved right.
Key terms for 1.5
Drag the curves yourself — the fastest way to make 1.5 stick.
Writing that a higher market price 'increases supply.' A higher price increases quantity supplied along a fixed curve; supply itself increases only when a determinant like input costs or technology shifts the curve right.
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