Which of the following principles emphasizes a cohesive effort under one commander?

The principle that emphasizes a cohesive effort under one commander is unity of command. This concept is crucial in military operations as it ensures that all forces involved in an operation are directed by a single commander. Unity of command facilitates better coordination, reduces confusion, and allows for clear objectives and priorities throughout the operation. When all personnel operate under one authority, it enhances the effectiveness of decision-making and the execution of plans, leading to synergistic and well-coordinated efforts. This principle is essential for maintaining focus on the mission and ensuring that all elements work towards achieving a common goal. Other principles, while important in their own right, do not specifically address the need for a single commander to unify efforts.