Which of the following best describes a fixed barrier?

A fixed barrier is best described as one that is permanently installed and difficult to move. Fixed barriers are designed to provide a stable and immovable line of defense in security settings. This permanence is crucial for maintaining continuous protection against unauthorized access or threats. By being inherently immobile, these barriers create a more reliable means of denying entry, as they cannot be easily bypassed or altered, unlike movable barriers which may provide flexibility but lack the same level of security.

The other options highlight characteristics of barriers that do not fit the definition of a fixed barrier. Some barriers that install quickly or adapt easily are typically temporary or mobile solutions, which do not provide the same level of long-term security. Similarly, barriers composed of movable material imply they can change position or be relocated, contradicting the concept of a fixed barrier. Lastly, while barriers that rely on weight can be effective in some situations, weight alone does not define a barrier as fixed, as it may still be movable or temporary depending on its structure and installation. Therefore, the defining characteristic of a fixed barrier lies in its permanence and the challenge it poses to unauthorized entry.