Explain the law of supply and what shifts a supply curve versus movement along it.
Supply is the amount producers are willing to make at each price. The law of supply: higher prices call forth more production — because at higher prices, harder and costlier production becomes worth doing. At $2 a jar, only the easy honey gets harvested; at $12, distant hives and hired help pay for themselves. Plotted, supply slopes upward.
Distinguish two motions. A price change moves you ALONG the existing curve. A change in the conditions of production — input costs, technology, number of sellers, taxes, expectations — SHIFTS the whole curve: at every price, more (or less) gets made. Cheaper fertilizer shifts wheat supply right; a drought shifts it left. Price moves along; conditions shift.
Mastery looks like: They state the law of supply with the cost logic behind it and sort along-vs-shift correctly.
Common stumbles: Calling every change a "shift"; thinking supply means what's in the warehouse rather than willingness-at-each-price.