A neuron was isolated from structure number 3 in the diagram above. When comparing the velocity of

28. A neuron was isolated from structure number 3 in the diagram above.
When comparing the velocity of action potentials, structure numbered 3 is much slower than that of structure numbered 4.
Which of the following explains why this is? See attached pic for the diagram
Select one:
a. Structure number 3 has a larger diameter than structure number 4.
b. Structure number 4 does not have myelin sheaths.
c. Structure number 3 does not have myelin sheaths.
d. Structure number 4 has a larger diameter than structure number 2.


27. When a single photon from a source of light hits the retina in the eye, it triggers a signal that travels along the optic nerve to the occipital lobe of the brain.
The interaction of a photon with the photoreceptors in the retina first causes the movement of sodium ions into a sensory neuron. What happens after the movement of sodium ions?
Select one:
a. Sodium ions move out of a sensory neuron.
b. Potassium ions move into an interneuron.
c. Potassium ions move out of a sensory neuron.
d. Sodium ions move into an interneuron.
my answer is c but not sure if its correct or not