What is the life cycle stage of fleas that remains hidden deep in carpet fibers?

The larvae stage of fleas is the correct answer because this stage of their life cycle is typically found hidden deep within carpet fibers, as well as in cracks, crevices, and other sheltered environments. Flea larvae are not visible to the naked eye and tend to move away from light, making them difficult to detect. They feed on organic debris, including adult flea feces, which provides the necessary nutrients for their development into the pupal stage.

In contrast, the pupae, while also hidden, are more likely to be found in cocoons closer to the surface as they prepare to emerge as adults. Adult fleas are usually found on their hosts or in high-traffic areas and are not hidden in carpets. Eggs, while they can fall into carpet fibers, are small and often stick to surfaces rather than embedding deeply within the fibers. Therefore, the larvae stage is the one that specifically remains concealed in carpets, making this choice the most accurate.