Which of the following is a way lifeguards can communicate while on patrol?

Lifeguards primarily use radios for communication while on patrol because they provide a reliable and immediate means of contact over long distances. Radios allow lifeguards to disseminate information quickly regarding emergencies, changes in conditions, or updates about potential hazards. This instant communication is crucial for ensuring safety and coordinating responses effectively, especially in situations where time is of the essence.

Other methods, like text messaging, may not be effective due to issues with connectivity in certain areas and the delay in exchanging messages compared to the immediacy of verbal communication through radios. Whistles can be used, but they are more suited for getting attention rather than facilitating detailed or ongoing communication. Visual signals, while useful in specific contexts (such as signaling from one lifeguard to another), do not provide the comprehensive communication capabilities that radios do, limiting their effectiveness in broader surveillance and emergency response scenarios. Thus, radios remain the standard tool for lifeguards to communicate while on patrol, ensuring they can work efficiently and safely together.