Biosignatures are observable characteristics or patterns that can indicate the presence of life or biological activity in a given environment. These can include chemical compounds, physical structures, or other features that are unique to living organisms. In astrobiology, the search for biosignatures is a key component of determining whether life exists or has existed elsewhere in the universe. Researchers use a variety of techniques and tools to identify and analyze potential biosignatures, with the goal of better understanding the conditions necessary for life to develop and thrive in different environments.