Final answer:
The large ears of a rabbit are all of the above: highly vascular, fragile and sensitive, and thermosensitive. They help regulate body temperature and detect subtle sounds for survival.
Step-by-step explanation:
The large ears of the rabbit serve multiple purposes, but in the context of this question, the correct answer is d) All of the above. The rabbit's ears are highly vascular, which helps regulate their body temperature, making them thermosensitive. With a rich supply of blood vessels, the ears can radiate heat away to cool the rabbit, or constrict to retain heat. The ears are also fragile and sensitive, allowing the rabbit to detect subtle sounds, which assists in identifying predators and other environmental cues. This sensitivity is linked to their auditory system, where the pinna, the outer part of the ear, contains receptors that convert mechanical waves into electrical signals for the brain to process. Notably, hair is a unique characteristic in the evolutionary history of rabbits, whereas the amniotic egg is shared between both rabbits and lizards but not frogs.