Biological markers, also known as biomarkers, are measurable indicators of biological processes or conditions within an organism. These markers can be found in various bodily fluids, tissues, or even genetic material, and are often used to assess health status, diagnose diseases, or evaluate treatment responses. Examples of biological markers include proteins, hormones, genes, or molecules that are associated with specific diseases or conditions. By detecting and measuring these markers, researchers and healthcare providers can gain insights into the underlying mechanisms of diseases and develop personalized treatment plans for patients.