( Selection ( ( ( ( is not ) ( ( a force ) ( in ( the sense ) ) ) ) ( that ( ( ( gravity or ) magnetism ) is ) ) ) . ) )
(ROOT (S (NP (NNP Selection)) (VP (VBZ is) (RB not) (NP (NP (DT a) (NN force)) (PP (IN in) (NP (DT the) (NN sense)))) (SBAR (IN that) (S (NP (NN gravity) (CC or) (NN magnetism)) (VP (VBZ is))))) (. .)))
Selection is not a force in the sense that gravity or magnetism is.
(ROOT (S (NP (NNP Gravity) (CC and) (NNP magnetism)) (VP (VBP are) (NP (DT both) (JJ common) (NNS forces))) (. .)))
Gravity and magnetism are both common forces.