How long can head lice survive away from the human body?

Head lice are parasitic insects that primarily live on the human scalp and feed on blood. When they detach from their human host, they have a limited capacity for survival. The correct answer states that head lice can survive away from the human body for up to 48 hours. This duration reflects their dependency on the warmth and nourishment provided by human blood. Beyond this time frame, they typically cannot survive due to dehydration and lack of food.

In examining the other options, it is important to note that while some may suggest a longer survival period, studies indicate that lice cannot thrive away from their host for extended times. The lifespan of head lice on objects like clothing or furniture depends greatly on environmental conditions such as humidity and temperature, which are typically less favorable away from the scalp. Thus, the answer indicating a survival time of up to 48 hours accurately reflects the life cycle of head lice and their biological needs.