Which of the following describes the roles of a squad automatic weapon (SAW) in the defense?

The role of a squad automatic weapon (SAW) in the defense is primarily to act as a principal direction of fire. This means that the SAW is used to provide a high volume of suppressive fire, allowing infantry units to defend their positions effectively against enemy forces. The SAW is designed for sustained fire and is typically employed to control key areas or to support maneuvering elements by disrupting enemy advances. Its ability to deliver accurate and continuous fire makes it crucial in shaping the battlefield during defensive operations, ensuring that enemy movements are deterred or defeated.

Other options do not align with the primary tactical functions of the SAW. For instance, while communication is essential for coordination during defense, it's not a role filled by the weapon. The SAW also does not serve as a means of transportation, which is typically provided by vehicles or other modes of troop movement. Conducting observations is important for situational awareness but is the responsibility of designated personnel rather than the SAW itself. Thus, the identification of the SAW as the principal direction of fire highlights its integral role in maintaining defensive strength and effectiveness.