Question

David regularly takes a pain reliever for his back pain. After a few weeks, he notices that he needs to increase the amount of pain-relieving drug that he takes each day in order to achieve the same level of pain relief. The phenomenon that David is experiencing is called:

Answer 1

a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question.

Step-by-step explanation:

Worthy examples may be the Aurora Borealis, the prowess of Michael Jordan, or the abilities of any given Marvel character blessed by exposure to radioactive materials.