The answer is B because its shows the subjects doing something
Explanation:
The paying capacity and the willingness of the buyer at a specific price is <em><u>demand</u></em>, while the quantity that is offered by the producers of those goods to its customers or consumers at a specific price is <em><u>supply</u></em>.
because, it is easier to use plants or things of that type other than using human trials which can be lethal if done wrong.
