[{"Bold_text": "noun", "List Items": ["a person or thing that precedes, as in a job, a method, etc.; predecessor.Synonyms: forerunner", "a person, animal, or thing that goes before and indicates the approach of someone or something else; harbinger:The first robin is a precursor of spring.Synonyms: herald", "Chemistry, Biochemistry.a chemical that is transformed into another compound, as in the course of a chemical reaction, and therefore precedes that compound in the synthetic pathway:Cholesterol is a precursor of testosterone.", "Biology.a cell or tissue that gives rise to a variant, specialized, or more mature form."]}]