Final answer:
Supply and demand are often inelastic in the short run and more elastic in the long run, causing prices to fluctuate more in the short run and quantities to fluctuate more in the long run.
Step-by-step explanation:
In most markets for goods and services, prices bounce up and down more than quantities in the short run, but quantities often move more than prices in the long run.
The underlying reason for this pattern is that supply and demand are often inelastic in the short run, so that shifts in either demand or supply can cause a relatively greater change in prices. However, since supply and demand are more elastic in the long run, the long-run movements in prices are more muted, while quantity adjusts more easily in the long run.