Which skill is critical for a lifeguard when dealing with potential emergencies?

The correct choice, which is first aid knowledge, is crucial for a lifeguard in emergency situations because it directly relates to the ability to respond effectively to injuries and health crises that may arise in or around the pool. lifeguards are often the first responders in emergencies involving drowning, injuries, or other medical issues, and having a solid understanding of first aid procedures—including CPR, wound care, and the management of various emergencies—enables them to act swiftly and efficiently to stabilize the situation and provide necessary care until advanced medical help arrives.

While effective communication is also important for coordinating with patrons and other lifeguards, and knowing swimming styles can enhance a lifeguard's ability to observe and identify swimmers' troubles, it is the lifeguard's ability to apply first aid that ultimately saves lives and mitigates injury severity during critical moments.