Test subjects are individuals or animals used in scientific experiments to study specific behaviors, reactions, or effects of treatments. They help researchers gather data and understand how different factors influence health, psychology, or biology. Test subjects can be volunteers or selected based on certain criteria, ensuring that the results are relevant and reliable. In medical research, test subjects may receive new medications or therapies to evaluate their safety and effectiveness. Ethical guidelines are in place to protect the well-being of test subjects, ensuring that their rights are respected throughout the research process. This is crucial for maintaining trust in scientific studies and advancements.