Statement A and Statement B

Statement A: Improper functioning of rod-shaped cells causes color blindness.
Statement B: The focal length of the human eye can be increased or decreased.

Explanation

Statement A: Improper functioning of rod-shaped cells causes color blindness.

Color blindness is a genetic disorder that affects the perception of colors. It is caused by a lack of or malfunctioning of cone cells in the retina of the eye. The retina contains two types of cells, rods and cones, which are responsible for detecting light and color, respectively.

Rod-shaped cells are responsible for detecting light in low light conditions, such as at night or in dimly lit environments. Cone-shaped cells are responsible for detecting color and are more concentrated in the center of the retina. The three types of cone cells are responsible for detecting red, green, and blue light.

Color blindness occurs when one or more of the cone cells are defective or absent. This results in an inability to distinguish certain colors, usually red and green. It is a genetic disorder that is passed down from parents to their children.

Therefore, Statement A is false as it is not the improper functioning of rod-shaped cells but the malfunctioning of cone-shaped cells that causes color blindness.

Statement B: The focal length of the human eye can be increased or decreased.

The focal length of the human eye is the distance between the lens and the retina. It determines the sharpness of the image that is formed on the retina. The lens of the eye is flexible and can change shape to adjust the focal length.

The process of adjusting the focal length is called accommodation. It is controlled by the ciliary muscles that are attached to the lens. When the ciliary muscles contract, the lens becomes more curved, and the focal length decreases, allowing the eye to focus on near objects. When the ciliary muscles relax, the lens becomes less curved, and the focal length increases, allowing the eye to focus on distant objects.

Therefore, Statement B is true as the focal length of the human eye can be increased or decreased by the process of accommodation.

Conclusion

In conclusion, Statement A is false as it is the malfunctioning of cone-shaped cells that causes color blindness, not rod-shaped cells. Statement B is true as the focal length of the human eye can be increased or decreased by the process of accommodation. Therefore, option C is the correct answer.