Final answer:
The ciliary muscle is responsible for altering the lens's shape to accommodate vision, enabling us to see at different distances through a process called accommodation. Option D is correct.
Step-by-step explanation:
The muscle that alters the shape of the lens to accommodate vision is the ciliary muscle. These muscles adjust the lens's shape and therefore its focal length, allowing it to focus light correctly onto the retina. This process enables us to see objects at various distances clearly, which is known as accommodation.
When the ciliary muscles contract, the lens becomes thicker and more convex for close vision, and when they relax, the lens becomes flatter for distant vision. The ability to focus on close objects diminishes with age, due to the reduced elasticity of the lens and weakening of the ciliary muscle, leading to conditions like presbyopia.
The muscle that alters the shape of the lens to accommodate vision is the Ciliary muscle. The ciliary muscle is located in the eye and plays a crucial role in adjusting the shape of the lens to allow for clear vision at different distances. When we focus on nearby objects, the ciliary muscle contracts, making the lens thicker.
This increases the lens' refractive power, allowing it to focus light properly on the retina. The muscles relax when we look at distant objects, making the lens thinner.