Question

small, uncharged substances enter and leave the cell membrane through the process of

endocytosis

simple diffusion

active transport

facilitated diffusion

Explanation:

To solve this, we analyze each option:

• Endocytosis: Involves engulfing large substances, not small/uncharged.
• Simple diffusion: Moves small, uncharged, non - polar substances across the membrane down concentration gradient, no energy/protein needed.
• Active transport: Requires energy, moves against gradient, often for larger/charged, not for small uncharged.
• Facilitated diffusion: Needs protein channels, for larger/polar, not small uncharged.

So the correct process for small, uncharged substances is simple diffusion.

Answer:

B. Simple diffusion