Tickets to a sporting event go on sale and sell out almost instantly. This implies that: Multiple Choice There are too many tickets to the event. The price for the tickets is below the equilibrium price. The tickets must be very expensive. There is a surplus of tickets.

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

here's one link :

the answer would be voluntary exchange -

"the act of buyers and sellers freely and willingly engaging in market transactions. moreover, transactions are made in such a way that both the buyer and the seller are better off after the exchange than before it occurred."

hope this : )

-shy

answer; ///after donning a gown, mask and eyewear;