Final answer:
This question is about the principles of supply and demand in economics, specifically related to equilibrium price and quantity.
Step-by-step explanation:
The concept being discussed in this question is Economics. Specifically, it pertains to the principles of supply and demand and how they interact to determine equilibrium price and quantity in a market.
1. At equilibrium, the quantity demanded is equal to the quantity supplied.
2. When demand declines and supply stays the same, the equilibrium quantity declines.
3. A supply schedule is determined by the wishes of sellers.
4. When the price is raised, the quantity supplied rises.