What is the difference between an individual demand curve and a market demand curve?

What is the reason that a supply curve is positively sloped?

1) An individual demand curve tells us the number of units demanded by an individual at different prices. As only a single individual is being considered, the slope of the demand curve is high. On the other hand, a market demand curve shows the total number of units demanded in the market at different prices. As all individuals are considered, the slope is relatively smaller.

2) A supply curve follows the law of supply according to which supply increases as prices increase. A positive slope manages to show this direct relation between price and supply.