Changes in the cost of inputs, natural conditions, technology and government decisions all affect the cost of production, and so how much firms are willing to supply at any given price. Panel (a) lists the changes that increase supply, shifting the curve out from S₀ to S₁: favorable natural conditions, a fall in input prices, improved technology, and lower product taxes or less costly regulations.
Panel (b) lists the same factors reversed, which decrease supply and shift the curve in from S₀ to S₁: poor natural conditions, a rise in input prices, a decline in technology (not common), and higher product taxes or more costly regulations.
Notice what is not on either list: the price of the product itself. A change in that price moves the economy along the supply curve (a change in quantity supplied); it does not shift the curve.