Final answer:
Graded potentials are temporary changes in the membrane voltage that can initiate an action potential if they add together to reach a threshold. They depend on the size of the stimulus and can result in depolarization or hyperpolarization.
Step-by-step explanation:
Graded potentials are the small, localized changes to membrane potential that "get an excitable tissue like a skeletal muscle cell to threshold." They are temporary changes in the membrane voltage that depend on the size of the stimulus.
Graded potentials can result in small changes of either depolarization or hyperpolarization, and if they add together or summate to reach a certain threshold, they can initiate an action potential.