The most logical answer would be an increase in demand.

• For instance, let's say that there is a new scientific study that shows that blueberries are able to prevent Alzheimer's disease. When this news hits consumers, they will naturally want more blueberries. This will result in a shift of the demand curve to the right and the resulting equilibrium point will have a higher price of blueberries as well as a higher quantity sold as farmers decide to produce more blueberries to fulfill the higher demand.