How do the biomes change as you go from west to east across the united states?

Aneuron is stimulated with an electric pulse. the action potential is detected at a point 3.70 cm down the axon 0.0052 s later.when the action potential is detected 7.20 cm from the point of stimulation, the time required is 0.0063 s. what is the speed of the electric pulse along the axon? (why are two measurements needed instead of only one? )

What feature of cell theory is best demonstrated in the image

Awave has a wavelength of 15 mm and a frequency of 6 hertz. what is its speed?