Answer: Plasma membrane.
- A Cell wall
- B Plasma membrane
- C Nuclear membrane
- D Endoplasmic reticulum
Correct answer: B. Plasma membrane
Explanation: Singer and Nicolson's fluid mosaic model (1972): plasma membrane is a fluid phospholipid bilayer with embedded proteins.
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.