Why constellation seems to have moved through the sky?

This means that we see the stars (andconstellations) drift from east to west every night.

The pizza is a neutral good. A neutral good is a good whose demand is not changed even though the income provided by the good is changed. A person's income can go either up or down, but their desire to buy more or less of Jamal's pizza will not change, so pizza sales will not go up or down. Demand and income are not tied to each other.