What is the name of the internal parasite that attacks young honeybees?

The correct answer is tracheal mite, which is a significant internal parasite that specifically targets the respiratory system of young honeybees. These microscopic mites infest the tracheae, which are the tubes through which bees breathe, leading to respiratory issues that can be detrimental to the bee's health and longevity.

In contrast, other choices represent different challenges that honeybees may encounter, but they do not specifically target young bees internally. The Varroa mite, for example, is an external parasite that feeds on the bodily fluids of adult bees and developing larvae, but it is not classified as an internal parasite. The small hive beetle primarily affects honeybee colonies by damaging honey and comb rather than attacking the bees themselves. Acarapis woodi, while also a type of tracheal mite, is an older term typically used to refer specifically to a species that had a significant impact historically but is not the most accurate term used in contemporary discussions about bee health and internal parasites.