Action potentials are all-or-none phenomena. this means that group of answer choices a) they must fire a certain number of times a second to communicate information accurately. b) they require a certain amount of stimulus to fire. c) the amplitude of the action potential is independent of the size of the stimulus. d) the amplitude of the action potential changes based on the intensity of the stimulus.

c) the amplitude of the action potential is independent of the size of the stimulus.

Explanation:

Conduction of nerve impulses through neurons is an all or none event. It means that either an axon would fire action potential to conduct the nerve impulse or it will not fire it. The firing of action potential requires the depolarization to reach the threshold level and depends on the strength of the stimulus. Once the stimulus is strong enough to reach the threshold, action potential would be fired. A stronger stimulus would produce the same effect, that is, it will produce the action potential of the same amplitude.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.