Final answer:
The statement that a rabbit's chest cavity is very small is True. Rabbits have a smaller thoracic cavity which houses essential organs like the heart and lungs, and the rib cage consists of true ribs, false ribs, and floating ribs to allow for respiratory movement.
Step-by-step explanation:
The statement that a rabbit's chest cavity is very small is True. The thoracic cavity, which includes the rib cage and the diaphragm, is smaller in rabbits compared to many other mammals. This cavity houses crucial organs such as the heart and lungs. The ribs, particularly in the case of rabbits, offer protection while still allowing for the necessary expansion and contraction during respiration.
The rib cage is divided into three groups: true ribs, false ribs, and floating ribs. The true ribs connect directly to the sternum, providing structural support for the thoracic cavity. False ribs and floating ribs have more flexible connections that allow for respiratory movement. Additionally, mammals have a "flow-through respiratory system", which may include air sacs that help reduce overall weight but are not found in rabbits, indicating that their body structure, including the thoracic cavity, may be comparatively restricted in size.
Overall, the smaller size of the rib cage in rabbits is part of an anatomical arrangement that supports their specific respiratory requirements and lifestyle.