+**Biological activity** describes the beneficial or adverse effects a substance has on a living [Organism](/wiki/organism). It is fundamental to [Pharmacology](/wiki/pharmacology) and toxicology, revealing how molecules interact with biological systems. These interactions drive cellular processes and can be measured through various assays.
+## See also
+- [Drug](/wiki/drug)
+- [Molecule](/wiki/molecule)
+- [Cell](/wiki/cell)
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