What is demand?
A change in demand describes a shift in consumer desire to purchase a particular good or service, irrespective of a variation in its price. The change could be triggered by a shift in income levels, consumer tastes, or a different price being charged for a related product.
what is supply
economics, supply is the amount of a resource that firms, producers, labourers, providers of financial assets, or other economic agents are willing and able to provide to the marketplace or to an individual. Supply can be in produced goods, labour time, raw materials, or any other scarce or valuable object.