The question is incomplete as it does not have the options which are:
A. endocytosis
B. active transport
C. facilitated diffusion
D. infusion
E. osmosis
Answer:
B. active transport
Explanation:
The neuron cell involves the influx and efflux of the sodium and potassium ions. These ions move through membrane proteins by facilitated diffusion and active transport.
The active transport allows the movement of ions against the concentration gradient that is even if the concentration of ions is higher.
In the given question, although the potassium ions are higher in the cytoplasm of the neuron, the potassium ions can enter the cell through active transport.
Because flu viruses evolve so quickly, last year's vaccine may not protect you from this year's viruses. New flu vaccines are released every year to keep up with rapidly adapting flu viruses.