The construction of demand and supply curves assumes that the primary variable influencing decisions to produce and purchase goods

The construction of demand and supply curves assumes that the primary variable influencing decisions to produce and purchase goods is the Price of the good.

Explanation:

All the other things influencing demand and supply curves respectively are kept constant and only price is the factor considered.

If the price of the good increases, then quantity supplied of the goods will increase and if the price decreases, then quantity supplied will decrease.

If the price of the good decreases, then quantity demanded of the goods will decrease and if the price increases, then quantity demanded will decrease.

Refer to the diagrams for demand and supply curves shapes.

you don't if you paid you paid. it's like if i bought a computer and used it then i say idon't want it anymore so im gonna return it. you can't. unlkess you have your reciept

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link :