A precursor is something that comes before another thing and often indicates or leads to its development. In various fields, such as science and technology, precursors can refer to substances or events that precede and influence a later outcome. For example, in chemistry, a precursor might be a compound that undergoes a reaction to form a more complex product. In a broader context, precursors can also refer to trends or ideas that foreshadow future developments. For instance, certain cultural movements can act as precursors to major societal changes. Understanding precursors helps in predicting and analyzing the evolution of ideas, technologies, and events in history.