In vitro testing refers to experiments conducted outside of a living organism, typically in a controlled laboratory environment, such as in petri dishes or test tubes. This method allows researchers to study cells in isolation, providing a simplified model to investigate cellular mechanisms, drug efficacy, and toxicity. In vivo testing, on the other hand, involves studying biological processes within living organisms. This can include animal models and, in later stages, human clinical trials. In vivo testing is critical for understanding the complex interactions within a whole organism, which cannot be replicated in vitro.
