NLN PAX Practice Exam 2025 – Complete Study Guide

The presence of cone cells in the retina is critical for color vision. Cone cells are photoreceptors that respond to different wavelengths of light, which correspond to different colors. If an animal's retina lacks cone cells, it would primarily rely on rod cells, which are more sensitive to light but do not contribute to color differentiation. Rod cells are responsible for vision in low light and can detect shades of gray but do not provide the ability to see color.

While the absence of cone cells certainly limits the animal's ability to perceive colors, it does not necessarily mean that the animal cannot see at all. Many animals can see in a limited capacity using only rod cells. Additionally, the ability to perceive depth and three-dimensional objects often relies on other visual cues and the function of rod cells, especially in low light conditions.

Therefore, the correct understanding is that an animal without cone cells would struggle to distinguish colors, but it may still be capable of seeing and perceiving some levels of detail in a grayscale format.