thErE is A DEliCAtE BAlAnCE oF nAturE ______ mAny squArE milEs oF oCEAn AnD vEgEtAtion AnD ClEAn Air ArE nEEDED to mAintAin only A rElAtivEly FEw humAn BEings.
A. whErE
B. in whiCh
C. whEn
D. how