Which of the following is NOT one of the four sources of drugs?

The four primary sources of drugs include plants, animals, synthetic processes, and minerals. These sources have historically served as the basis for drug development, with many medications derived from natural substances (plants and animals) or created through chemical synthesis (synthetic).

Water, while essential for life and used in various pharmaceutical preparations as a solvent, does not have properties that allow it to be classified as a source of drugs. It serves as a vehicle for delivering medications rather than being a source of medicinal compounds itself. Understanding these sources is crucial for recognizing how various drugs are developed and the importance of each in pharmacology.