( ( ( The retina ) ( contains ( millions ( of ( light-sensitive cells ) ) ) ) ) ( , ( ( called ( ( ( ( rods and ) cones ) , ) ( which ( ( convert ( the image ) ) ( into ( ( a pattern ) ( of ( nerve impulses ) ) ) ) ) ) ) ) . ) ) )
(ROOT (SINV (S (NP (DT The) (NN retina)) (VP (VBZ contains) (NP (NP (NNS millions)) (PP (IN of) (NP (JJ light-sensitive) (NNS cells)))))) (, ,) (VP (VBD called)) (NP (NP (NNS rods) (CC and) (NNS cones)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBP convert) (NP (DT the) (NN image)) (PP (IN into) (NP (NP (DT a) (NN pattern)) (PP (IN of) (NP (NN nerve) (NNS impulses))))))))) (. .)))
The retina contains millions of light-sensitive cells, called rods and cones, which convert the image into a pattern of nerve impulses.
(ROOT (S (NP (NP (DT The) (JJ light-sensing) (NNS cells)) (PP (IN in) (NP (DT the) (NN retina)))) (VP (VBP are) (VP (VBN called) (NP (NNS rods) (CC and) (NNS cones)))) (. .)))