FDA recommends that you provide your rationale for the selection of particular animal models for your animal study. The animal and its related environmental and physiologic attributes should provide a test system that offers a best attempt at simulating the clinical setting. The rationale for the conduct of an animal study should clearly state which of the elements of your risk analysis will be addressed and why the particular animal model was selected. If there are limitations to the animal model such that certain risks of the device are best addressed by bench or cadaver testing, these relationships should be described. Your rationale should also describe inherent challenges to the test system, such as: