What is the primary function of life jackets?

The primary function of life jackets is to keep you afloat in water, which is crucial for safety in boating and other water activities. They are designed to help prevent drowning by providing buoyancy and support, allowing a person to stay on the surface of the water until help arrives or they can reach safety. While keeping warm can be an ancillary benefit in colder waters, the main purpose of a life jacket is its flotation aspect, ensuring that an individual remains above water.

The other options, although they may have some relevance to safety while on the water, do not encompass the fundamental role of life jackets. Providing visibility can be associated with brightly colored life jackets, but this is secondary to their primary aim of flotation. Similarly, protecting against sun exposure or storing personal items safely are functions that are not related to the essential purpose of life jackets.