Final answer:
The subcutaneous route of medication administration delivers medicine to the layer of fat just below the skin. It is a parenteral method used when oral administration is not suitable.
Step-by-step explanation:
The subcutaneous route of medication administration delivers medicine into the layer of fat just below the skin. This method is part of the parenteral routes of drug delivery and is used when a drug is not suitable for oral administration, either because it is not absorbed well in the gastrointestinal (GI) tract, or if the patient is unable to take medications orally due to illness. Subcutaneous injections are often used for vaccines, insulin, and other medications that require a slow, steady release into the bloodstream.