Which of the following is NOT a source of medication?

The choice indicating machines as not being a source of medication is accurate because medications are derived from various natural and synthetic origins, primarily from chemicals, plants, and animals.

Chemicals serve as the foundational elements in the formulation of many pharmaceuticals, either as active ingredients or as additives that enhance the effectiveness or stability of drugs. Plants are another significant source, providing a range of compounds that are utilized for their therapeutic properties. Many traditional and modern medications are derived from botanicals or synthesized in ways that emulate plant compounds.

Animals also contribute to the medication landscape; for instance, certain hormones and enzymes have traditionally been sourced from animal tissues.

Machines, however, do not produce medicines but instead serve as tools for processing and delivering medications, helping in the production and distribution process. Thus, they do not qualify as a source of medication in the same way that the other categories do.