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(a) (i) Explain the changes that take place in the pupil and iris of a human eye when a person moves from a dark room to a room with bright light.
(ii) What is the significance of the changes explained in (a) above.
(b) How does the human eye obtain nutrients?
(c) Explain why images that form on the blind spot are not perceived.

Answer Text:
(a)(i) Circular muscles of the iris contract while radial muscles relax reducing the size of the
pupil, causing less light enters the eye
(ii) The retina is protected from damage from too much light.
(b) Choroid has a dense network of blood capillary from which nutrients diffuse out to supply the eye.

(c) The blind spot has no photoreceptors cells that is, rods and cones hence no impulses generated to be transmitted to the brain for interpretation.