( ( ( ( ( Light ( ( enters ( the eye ) ) ( through ( the pupil ) ) ) ) , ) and ) ( ( the pupil ) ( is ( ( made ( ( larger or ) smaller ) ) ( by ( the iris ) ) ) ) ) ) . )
(ROOT (S (S (NP (NNP Light)) (VP (VBZ enters) (NP (DT the) (NN eye)) (PP (IN through) (NP (DT the) (NN pupil))))) (, ,) (CC and) (S (NP (DT the) (NN pupil)) (VP (VBZ is) (VP (VBN made) (S (ADJP (JJR larger) (CC or) (JJR smaller))) (PP (IN by) (NP (DT the) (NNS iris)))))) (. .)))
Light enters the eye through the pupil, and the pupil is made larger or smaller by the iris.
(ROOT (S (NP (NP (DT The) (NN pupil)) (PP (IN of) (NP (DT the) (NN eye)))) (VP (VBZ allows) (ADJP (JJ light) (S (VP (TO to) (VP (VB enter)))))) (. .)))
The pupil of the eye allows light to enter.