Physiology All the following are characteristics of the plasma membrane except: A It serves as a selective transpo route through the facilitation of both active and passive transpo. B It possesses a thickness of 1 to 2 mm. C It is involved in the generation of ionic gradients between the cytoplasm and the external environment. D It serves as a sensor of signals from the extracellular environment. 💡 Explanation All the following are characteristics of the plasma membrane except: ✓ Correct Answer: B. It possesses a thickness of 1 to 2 mm.