A) as the action potential passes down the axon; a more negatively charged axon cytoplasm​
B) ​when the threshold potential is reached; the opening of more sodium channels
C) ​during the resting potential; the diffusion of sodium ions into the axon cytoplasm
D) ​when the action potential reaches the axon terminal; a more positively charged axon cytoplasm
E) ​when neurotransmitters attach to dendrite receptors; no difference in the charge of the axon cytoplasm

A) ​spinal cord injury
B) ​Huntington disease
C) ​amyotrophic lateral sclerosis
D) ​Alzheimer's disease
E) multiple sclerosis​

A) ant​
B) ​eagle
C) ​sponge
D) ​fruit fly
E) ​earthworm