Answer: Changes in membrane potential.
- A Concentration gradient
- B Changes in membrane potential
- C Ligand binding
- D Temperature only
Correct answer: B. Changes in membrane potential
Explanation: Voltage-gated channels (e.g., Na+ channels in neurons) open when membrane potential reaches a threshold (depolarization).
Animal cell structure with major organelles labeled. Image: LadyofHats (Mariana Ruiz), Public Domain, via Wikimedia Commons.
Concept context
Cell theory, prokaryotic vs eukaryotic cells, organelles and their functions. Foundation of all biology.