( It ( ( was ( believed ( that ( ( ( the head ) ( of ( a ( sperm allready ) ) ) ) ( containes ( ( a ( tiny creature ) ) ( resembling ( the ( later adult ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBD was) (VP (VBN believed) (SBAR (IN that) (S (NP (NP (DT the) (NN head)) (PP (IN of) (NP (DT a) (NN sperm) (NN allready)))) (VP (VBZ containes) (NP (NP (DT a) (JJ tiny) (NN creature)) (VP (VBG resembling) (NP (DT the) (JJ later) (NN adult))))))))) (. .)))
It was believed that the head of a sperm allready containes a tiny creature resembling the later adult.
(ROOT (S (NP (NP (DT The) (NN head)) (PP (IN of) (NP (DT the) (NN sperm)))) (VP (VBZ contains) (NP (DT the) (NN nucleus))) (. .)))
The head of the sperm contains the nucleus.