a. Increase in input prices: Increase in price of factors of production (rent, wages, interest and profit) influence the cost of production of a commodity and thereby its supply. An increase in price of inputs, will increase the cost of production leading to a reduction in profit. This will make the producer reduce the supply of the commodity, shifting the supply curve to the left. b. Reduction in per unit tax: Government imposes many taxes on production of goods, etc. Such taxes affect supply because it adds to the cost of production. Reduction in per unit tax levied by the government will decrease the cost of production and increase supply by the firms due to higher profit margins. In this case the supply curve will shift towards the right.