Final answer:
The fovea has a higher density of cones compared to the periphery in humans, primates, and rats.
Step-by-step explanation:
In humans, primates, and rats, the fovea has a higher density of cones compared to the periphery. The fovea is responsible for acute vision and has a high concentration of cones, which are photoreceptor cells that work best in bright light and are responsible for high-resolution vision.
On the other hand, the periphery of the retina contains more rods, which are specialized photoreceptor cells that work better in low light conditions. The ratio of cones to rods is much higher in the fovea compared to the periphery.