What does Locard's Exchange Principle state?

Locard's Exchange Principle is foundational in forensic science, stating that with every contact between a person and an object or another person, a transfer of material occurs. This means that whenever someone interacts with their environment, they leave behind traces of that contact and, at the same time, take away traces from the environment with them. This principle is essential for crime scene investigations, as it emphasizes the significance of physical evidence.

In practical terms, it implies that evidence, such as hair, fibers, or fingerprints, can be used to link a suspect to a crime scene or victim. Investigators use this principle to collect and analyze evidence to build connections and reconstruct events based on the traces left behind. Understanding Locard's Exchange Principle helps in recognizing the importance of thorough evidence collection and the careful evaluation of potential traces at a crime scene, which is critical for successful investigations. Therefore, the option stating that every contact leaves a trace and takes a trace aligns directly with the core concept of Locard's principle.