**Question:** Rods and cones differ in all except

A. Sensitivity to light
B. Sensitivity to color
C. Location in the retina
D. Response time

**Core Concept:** Rods and cones are types of photoreceptor cells in the retina, responsible for vision in low light conditions (rods) and color perception (cones).

**Why the Correct Answer is Right:** Rods and cones differ in terms of their functions and light sensitivity. Rods are more sensitive to low light levels, while cones are responsible for color vision in normal light conditions. Sensitivity to light (option A) is the key difference between rods and cones, and is the reason rods are more important for nocturnal vision.

**Why Each Wrong Option is Incorrect:**

A. Sensitivity to color (option B) is a characteristic of cones, not rods.
B. Response time refers to the time it takes for the photoreceptor cells to respond to light stimulation, not a characteristic unique to rods or cones. Both types of photoreceptor cells have similar response times.
C. Location in the retina (option C) is a difference between rods and cones, with rods primarily located in the peripheral retina and cones concentrated in the central retina, known as the macula.
D. Response time (option D) is not a unique characteristic of rods or cones, as both types of photoreceptor cells have similar response times.

**Clinical Pearl:** Understanding the differences between rods and cones is essential for clinicians to diagnose and manage retinal disorders like retinitis pigmentosa, which primarily affects rods, leading to night blindness, or Stargardt disease, which affects cones and results in macular degeneration.

**Correct Answer:** C. Location in the retina (option C) is the exception in the list of differences between rods and cones. Rods are mainly located in the peripheral retina, while cones are concentrated in the central retina, particularly in the macula, which is responsible for sharp vision and color perception.