Which one of the following is an example of simple diffusionSelect one:a. Sodium influx via voltage gated sodium channelb. Amino acid transport from intestinal lumen into the cellsc. Glucose transport from intestinal cells to the bloodd. Glucose transport from intestinal lumen into the cells

The correct answer is a. Sodium influx via voltage gated sodium channel.

Here's why:

Simple diffusion is a passive process that allows small, nonpolar molecules to move from an area of high concentration to an area of low concentration across a membrane. It does not require energy or the assistance of transport proteins.

a. Sodium influx via voltage gated sodium channel: This is an example of facilitated diffusion, not simple diffusion. Voltage gated channels are a type of protein that can open and close in response to changes in voltage across a membrane. They facilitate the transport of ions like sodium across the membrane.

b. Amino acid transport from intestinal lumen into the cells: This is an example of active transport. Amino acids are large, polar molecules that cannot cross the lipid bilayer of the cell membrane by simple diffusion. They require transport proteins and energy to move across the membrane.

c. Glucose transport from intestinal cells to the blood: This is also an example of active transport. Glucose is a large, polar molecule that requires transport proteins and energy to move across the cell membrane.

d. Glucose transport from intestinal lumen into the cells: This is another example of active transport. Like amino acids, glucose cannot cross the cell membrane by simple diffusion. It requires transport proteins and energy to move across the membrane.