Which tool can be used to manage services running on a Linux system?

The correct answer is systemctl, which is the primary tool used to manage services on modern Linux systems that employ systemd as their init system. This command provides a unified interface for controlling services, managing the state (start, stop, restart, enable, disable), checking the status of services, and even dealing with dependency management between them. Systemctl replaces other older service management commands and encapsulates a broader range of system management capabilities beyond just handling services.

In contrast, while the command "service" has traditionally been used in SysVinit-based systems to start and stop services, it does not provide the same extensive features or modern management practices as systemctl does. Moreover, "servicectl" does not exist as a known command in either systemd or SysVinit environments, making it an incorrect choice. Lastly, "manage-services" is not recognized as a standard command within Linux distributions, further solidifying systemctl’s position as the correct answer in contemporary Linux service management.