Final answer:
The statement is true; sodium is the predominant cation in blood plasma, and potassium is the predominant cation in intracellular fluid.
Step-by-step explanation:
The statement that sodium is the predominant cation in blood plasma, while potassium is the predominant cation in intracellular fluid is true.
Sodium (Na+) is the major cation of the extracellular fluid (ECF) and plays a crucial role in generating osmotic pressure gradient between the interior of cells and their surroundings.
On the other hand, potassium (K+) is the principal ion within cells and is essential for establishing the resting membrane potential, especially in neurons and muscle fibers following depolarization and action potentials.
The sodium-potassium pumps in cell membranes work to actively transport sodium out of the cell and potassium into the cell, maintaining the correct concentration gradients despite the natural tendency for sodium to enter and potassium to exit the cell.