Which type of receptors in the retina are necessary for visual perception in dim light?

The correct choice is rods, as they are specifically designed for vision in low-light conditions. Rods are photoreceptor cells located in the retina that are highly sensitive to light, making them essential for night vision and in environments with minimal illumination. They do not detect color, which is why vision in dim light often appears in shades of gray.

Rods play a crucial role in peripheral vision and are more numerous than cones in the human retina, particularly in the outer regions. Their ability to respond to lower levels of light allows humans to perceive shapes and movements even when illumination is scarce. In contrast, cones, which are another type of photoreceptor, are responsible for color vision and function best in bright light, making them less effective for visual perception in dim circumstances.

Bipolar cells and ganglion cells, while important for transmitting and processing the visual information received from rods and cones, do not directly contribute to light sensitivity themselves; they are involved in the overall process of visual signaling rather than the initial light detection performed by rods and cones.