What distinguishes a solution from a suspension?

A solution is a homogeneous mixture where the solute is completely dissolved in the solvent, resulting in a clear liquid without settled particles. The characteristic that allows a solution to be commonly used in injections is its stability and uniformity. When a solution is administered, it provides consistent dosage and immediate availability of the active ingredient to the body, making it suitable for medical applications.

In contrast, suspensions contain solid particles that are not dissolved and may settle out over time, which requires agitation prior to use to ensure proper dosing. Therefore, options relating to settled particles or the need for shaking do not apply to solutions, while the distinction of being suitable for injections highlights the clarity and reliability of a solution when used in medical contexts.