Final answer:
An improvement in technology that reduces the cost of production will cause an increase in supply, while companies believing that the product's selling price will go up does not directly cause an increase in supply.
Step-by-step explanation:
An improvement in technology that reduces the cost of production will cause an increase in supply. This can be shown as a rightward (or downward) shift in the supply curve. For example, if a new machine is invented that allows a company to produce more goods at a lower cost, they will be able to supply more of the product in the market.
Companies believe that the product's selling price will go up. While this may be true in some cases, it does not directly cause an increase in supply. The decision to increase supply is based on the cost of production, not the selling price.