Define "physical barriers" in security.

Physical barriers in security refer to tangible structures or devices that are designed to prevent unauthorized access to a property or facility. These include items such as fences, walls, gates, and locks, which serve as the first line of defense in a security strategy. The primary purpose of these barriers is to deter would-be intruders and protect vulnerable areas or assets.

When effectively implemented, physical barriers create a controlled environment where access can be monitored and limited. For instance, a high fence surrounding a property not only acts as a deterrent but also establishes a clear boundary that delineates private property. Locks on doors ensure that access is restricted to authorized individuals, enhancing the overall security of the facility.

In contrast, the other options presented focus on different aspects of security that do not fall under the definition of physical barriers. Security protocols for IT systems involve measures to protect digital assets rather than physical spaces. Policies for employee behavior address guidelines for how personnel should act within an organization but do not involve actual barriers. Training programs for staff aim to improve awareness and preparedness among employees but are not physical constructs that restrict access. Thus, the correct answer highlights the essential role that physical barriers play in security measures.