It's kind of a, which is the cause and which is the effect, question.
( It ( ( 's ( kind ( of ( ( a , ) ( which ( is ( ( ( the cause ) and ) ( which ( is ( ( ( the effect ) , ) question ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ 's) (NP (NP (NN kind)) (PP (IN of) (NP (NP (SYM a)) (, ,) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (NP (DT the) (NN cause)) (CC and) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (NP (DT the) (NN effect)) (, ,) (NP (NN question)))))))))))))) (. .)))
There's no question of which is the cause.
( There ( ( 's ( ( no question ) ( of ( which ( is ( the cause ) ) ) ) ) ) . ) )
(ROOT (S (NP (EX There)) (VP (VBZ 's) (NP (NP (DT no) (NN question)) (PP (IN of) (SBAR (WHNP (WDT which)) (S (VP (VBZ is) (NP (DT the) (NN cause)))))))) (. .)))