Where are modules required to support a kernel stored in a Linux system?

In a Linux system, kernel modules are stored in the directory designated as /lib/modules. This location is specifically structured to match the kernel version for which the modules are intended. When a kernel is loaded, it can dynamically load or unload these modules, allowing the kernel to utilize additional functionalities without requiring a reboot. The modules can include drivers and other necessary pieces of code that enhance the capabilities of the kernel while maintaining its core efficiency.

The other options are not standard locations for kernel modules. The /usr directory typically contains user binaries, libraries, and documentation rather than kernel-specific modules. The /etc directory is primarily for configuration files, where system-wide settings are stored, and does not contain loadable kernel modules. Similarly, /var is used for variable data that changes frequently, such as logs and temporary files, and is not associated with module storage. Therefore, /lib/modules is the correct and expected location for modules required to support a kernel in a Linux system.