Final answer:
Rabbits have a specialized digestive system that allows them to digest food twice and produce cecotrophes, which they re-ingest for further nutrient extraction. However, this system does not permit them to vomit, making option (c) the correct answer.
Step-by-step explanation:
The unique anatomical make-up of the rabbit's gastrointestinal (GI) system due to its enlarged small intestine and cecum allows for a more extensive digestion process of plant material. Specifically, rabbits have an adaptation wherein they digest their food twice. During the first pass through the GI system, food collects in the cecum, where it forms into soft feces known as cecotrophes, which are then re-ingested by the rabbit to further extract nutrients. This process, called coprophagy, relies on the important function of the cecum and its bacterial population to break down plant fibers and produce vital nutrients. As a result of these specific adaptations, the statement that a rabbit cannot have diarrhea is incorrect, as they can indeed experience it. On the other hand, because of this specialized digestive system, notably the absence of certain reflexes and muscle configurations, a rabbit cannot vomit, making option (c) the correct answer to the student's question.