Final answer:
Red blood cell membranes react to different solutions based on osmolarity: they maintain shape in isotonic solutions and may swell or shrink in hypotonic and hypertonic solutions, respectively. The correct answer is (b) Isotonic; Hypotonic; Isotonic.
Step-by-step explanation:
When red blood cells (RBCs) are exposed to different solutions, their membranes react in distinct ways depending on the osmolarity of the surrounding solution:
- Isotonic solution: RBCs will retain their normal shape as the flow of water in and out of the cells is balanced.
- Hypotonic solution: RBCs will swell and may rupture because water enters the cells faster than it leaves, diluting their contents.
- Hypertonic solution: RBCs will shrink or shrivel as water leaves the cell, diluting the surrounding environment.
The correct answer to the question is (b) Isotonic; Hypotonic; Isotonic. When RBCs are exposed to isotonic or hypotonic solutions, their membranes stay intact and will cause the solution to be isotonic.