Why does the supply curve slope upward

Question

Explain the law of supply. Why does the supply curve slope upward?

Answer 1

As prices rise because of increased demand for a commodity, producers find it more and more profitable to increase the quantity they offer for sale whereas supply curve will slope upward from left to right.  Clearly, firms would rather sell at a higher price than at a lower price.  Furthermore, it is essential for firms to demand a higher price as they increase production.  This comes about because as they produce more, they initiate to run up against capacity constraints and costs rise. As manufacturing increases firm will need to add an extra shift and then a third shift, mutually conceivably at higher wages.  It may run out of warehouse space and have to rent at higher cost from another firm.