( Incubation ( ( ( ( isfound ( almost exclusively ) ) ( in birds ) ) ( where ( ( the eggs ) ( are ( warmed ( sothis ( refers ( to ( ( ( caring ( for ( the eggs ) ) ) and ) ( keeping ( them warm ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNP Incubation)) (VP (VBD isfound) (ADVP (RB almost) (RB exclusively)) (PP (IN in) (NP (NNS birds))) (SBAR (WHADVP (WRB where)) (S (NP (DT the) (NNS eggs)) (VP (VBP are) (ADJP (VBN warmed) (SBAR (S (NP (NNS sothis)) (VP (VBZ refers) (PP (TO to) (S (VP (VP (VBG caring) (PP (IN for) (NP (DT the) (NNS eggs)))) (CC and) (VP (VBG keeping) (S (NP (PRP them)) (ADJP (JJ warm))))))))))))))) (. .)))
Incubation isfound almost exclusively in birds where the eggs are warmed sothis refers to caring for the eggs and keeping them warm.
(ROOT (S (NP (NNP Incubation)) (VP (VBZ is) (SBAR (WHADVP (WRB when)) (S (NP (NNS birds)) (VP (VBP keep) (S (NP (PRP$ their) (NNS eggs)) (ADJP (JJ warm)) (SBAR (IN while) (S (NP (DT the) (NNS embryos)) (ADVP (RB inside)) (VP (VB develop))))))))) (. .)))
Incubation is when birds keep their eggs warm while the embryos inside develop.