Which of the following is an example of an isotonic solution?

An isotonic solution has the same osmotic pressure as physiological body fluids, meaning it does not cause cells to swell or shrink when introduced into the bloodstream. This is important in IV therapy as it helps maintain fluid balance without disturbing cellular integrity.

Both 0.9% NaCl (normal saline) and Lactated Ringer's solution are classified as isotonic solutions. Normal saline is often used in various clinical settings for fluid replacement and as a diluent for medications. Lactated Ringer's solution contains electrolytes and is also isotonic, making it suitable for restoring fluid and electrolyte balance, particularly in patients undergoing surgery or experiencing dehydration.

Using isotonic solutions helps to ensure that there is no net movement of water into or out of the cells, which is crucial for maintaining homeostasis during intravenous therapy. Thus, the recognition that both 0.9% NaCl and Lactated Ringer's solution are isotonic is why the correct option encompasses both of them.