From thE inFormAtion givEn in thE pAssAgE, thE Author's mAin ConCErn is thAt _________.
A．thE EnvironmEnt wEll-BEing AnD our hEAlth ArE rElAtED
B．thE EnvironmEnt AnD thE rEsults oF our ExErCising is rElEvAnt
C．thE EvEr ChAnging living stAnDArDs DEmAnD morE From thE EnvironmEnt
D．thE BAlAnCE oF EnvironmEnt AnD EConomiC DEvElopmEnt is vitAl For thE soCiEty