( ( ( ( ( A ( true ( breeding organism ) ) ) , ) ( sometimes ( also ( called ( a pure-bred ) ) ) ) ) , ) ( ( is ( ( an organism ) ( that ( always ( ( ( passes down ) ( a ( certain ( phenotypic trait ) ) ) ) ( to ( its offspring ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (JJ true) (NN breeding) (NN organism)) (, ,) (VP (ADVP (RB sometimes)) (ADVP (RB also)) (VBD called) (NP (DT a) (NN pure-bred))) (, ,)) (VP (VBZ is) (NP (NP (DT an) (NN organism)) (SBAR (WHNP (WDT that)) (S (ADVP (RB always)) (VP (VBZ passes) (PRT (RP down)) (NP (DT a) (JJ certain) (JJ phenotypic) (NN trait)) (PP (TO to) (NP (PRP$ its) (NN offspring)))))))) (. .)))
A true breeding organism, sometimes also called a pure-bred, is an organism that always passes down a certain phenotypic trait to its offspring.
(ROOT (S (NP (JJ Selective) (NN breeding)) (VP (VBZ involves) (S (VP (VBG choosing) (NP (JJ certain) (NNS organisms)) (S (VP (TO to) (VP (VB reproduce) (PP (IN with) (NP (CD one) (DT another))) (SBAR (IN in) (NN order) (S (VP (TO to) (VP (VB pass) (PP (IN on) (NP (JJ specific) (, ,) (JJ desirable) (NNS traits))) (PP (TO to) (NP (PRP$ their) (NN offspring))))))))))))) (. .)))
Selective breeding involves choosing certain organisms to reproduce with one another in order to pass on specific, desirable traits to their offspring.