What primarily causes buoyancy in the body after drowning?

Buoyancy in the body after drowning is primarily influenced by the process of decomposition, which leads to gas formation. When a body is submerged in water, the tissues start to break down gradually after death. This decomposition produces gases, such as methane, carbon dioxide, and others, which accumulate within the body. The formation of these gases increases the body's buoyancy, allowing it to rise to the surface after a period.

While trapped air in the lungs may initially contribute to buoyancy when a person drowns, it is not the primary cause of buoyancy for a body after death. Furthermore, weight loss from immersion and inflammation of body tissues are not significant factors in buoyancy related to drowning. The overarching process of decomposition and gas accumulation is the critical factor that determines whether a body will float or remain submerged, making it the most relevant cause of buoyancy in this context.