Which is an obvious sign of death that BLS personnel may observe?

An obvious sign of death that BLS personnel may observe is rigor mortis and total incineration. Rigor mortis, which refers to the stiffening of muscles after death, typically sets in a few hours postmortem and indicates that biological processes have ceased. Its presence can provide a clear indication that an individual is deceased.

Total incineration also serves as an unequivocal sign of death, as it implies that the body's tissues have been entirely consumed by fire, rendering any signs of life impossible. In both instances, these signs are definitive and can be observed by trained personnel, making them critical indicators in assessing whether resuscitation efforts should continue or if a patient has indeed passed.

Other options like warmth to the touch, a pulsing heartbeat, and respiratory effort are all signs that may indicate life or conditions where resuscitation might still be viable. In contrast, rigor mortis and total incineration unequivocally signify that life functions have permanently ceased.