Cones and rods are helpful respectively in 

Options

A. dimlight vision, colour vision
B. colour vision, dimlight vision
C. color vision only
D. dimlight vision only

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the functions of cones and rods in the human eye. We need to identify what each type of photoreceptor is responsible for.

2. **Identifying Photoreceptors**: There are two main types of photoreceptors in the retina: cones and rods.

3. **Function of Rods**: Rods are photoreceptors that are sensitive to low light levels. They enable vision in dim light conditions but do not detect color. Therefore, rods are primarily responsible for night vision or vision in low-light environments.

4. **Function of Cones**: Cones, on the other hand, are photoreceptors that function best in bright light. They are responsible for color vision and detail. Cones allow us to perceive different colors due to the presence of pigments such as iodopsin.

5. **Conclusion**: Based on the functions of rods and cones:
- Cones are responsible for color vision.
- Rods are responsible for dim light vision.

6. **Selecting the Correct Option**: Given the options provided:
- Option A: Dim light vision and color vision
- Option B: Color vision, dim light vision
- Option C: Color vision only
- Option D: Dim light vision only

The correct answer is **Option B**: Cones help in color vision, and rods help in dim light vision.