( ( ( ( ( The retina ) , ) ( which ( covers ( ( the back ) ( of ( ( the inside ) ( of ( the eyeball ) ) ) ) ) ) ) ) , ) ( ( contains ( ( cones and ) ( ( rods-two types ) ( of ( light-sensitive cells ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NN retina)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ covers) (NP (NP (DT the) (NN back)) (PP (IN of) (NP (NP (DT the) (NN inside)) (PP (IN of) (NP (DT the) (NN eyeball))))))))) (, ,)) (VP (VBZ contains) (NP (NP (NNS cones)) (CC and) (NP (NP (JJ rods-two) (NNS types)) (PP (IN of) (NP (JJ light-sensitive) (NNS cells)))))) (. .)))
The retina, which covers the back of the inside of the eyeball, contains cones and rods-two types of light-sensitive cells.
(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)))) (. .)))