( ( 3 . ) ( ( Decomposers - ) ( ( are ( in ( charge ( of ( ( ( ( ( cleaning up ) ( the environment ) ) ( by decomposing ) ) and ) ( ( freeing ( dead matter ) ) ( for ( ( recycling back ) ( into ( the ecosystem ) ) ) ) ) ) ) ) ) ) . ) ) )
(ROOT (S (LST (LS 3) (. .)) (NP (NNP Decomposers) (NNP -)) (VP (VBP are) (PP (IN in) (NP (NP (NN charge)) (PP (IN of) (S (VP (VP (VBG cleaning) (PRT (RP up)) (NP (DT the) (NN environment)) (PP (IN by) (S (VP (VBG decomposing))))) (CC and) (VP (VBG freeing) (NP (JJ dead) (NN matter)) (PP (IN for) (S (VP (VBG recycling) (PRT (RP back)) (PP (IN into) (NP (DT the) (NN ecosystem))))))))))))) (. .)))
3. Decomposers- are in charge of cleaning up the environment by decomposing and freeing dead matter for recycling back into the ecosystem.
(ROOT (S (NP (NP (DT A) (JJ primary) (NN role)) (PP (IN of) (NP (NP (NNS decomposers)) (PP (IN in) (NP (DT an) (NN ecosystem)))))) (VP (VBZ is) (SBAR (IN that) (S (NP (PRP they)) (VP (VBZ cycle) (NP (NN matter)) (PP (IN by) (S (VP (VBG returning) (NP (NN carbon) (CC and) (JJ other) (NN matter)) (PP (TO to) (NP (DT the) (NN ecosystem)))))))))) (. .)))
A primary role of decomposers in an ecosystem is that they cycle matter by returning carbon and other matter to the ecosystem.