Final answer:
Doctrine refers to the principles that guide the composition of joint forces. Joint forces do not require equal parts of all the Services; the proper mix of Service components depends on the specific mission and requirements. This allows for flexibility and the ability to tailor the force to the mission at hand.
Step-by-step explanation:
Doctrine refers to the principles or beliefs that guide a particular group or organization. In the context of the question, it is referring to the principles that guide the composition of joint forces.
Joint forces do not require equal parts of all the Services. Instead, the proper mix of Service components within a joint force is determined based on the specific mission and requirements. This means that different missions may require different proportions of each Service component.
For example, if a mission involves primarily air operations, the joint force may have a larger proportion of Air Force components compared to the other Services. Similarly, if the mission involves amphibious operations, the joint force may have a larger proportion of Marine Corps components. The goal is to achieve the right force for the mission, considering factors such as capabilities, expertise, and resources.