Explanation:
Preventive controls are to stop something from happening. These can include locked doors that keep intruders out, user training on potential harm (to keep them vigilant and alert), or even biometric devices and guards that deny access until authentication has occurred. By disabling all unnecessary services you would be reducing the attack surface because then there is less opportunity for risk incidents to happen. There are many risks with having many services enabled since a service can provide an attack vector that someone could exploit against your system. It is thus best practice to enable only those services that are absolutely required.