it CAn BE inFErrED From thE thirD pArAgrAph thAt EArliEr gEnErAtions DiDn't rEAlizE
A．thE intErDEpEnDEnCE oF wAtEr, soil, AnD living things
B．thE importAnCE oF thE propEr usE oF lAnD
C．thE hArmFulnEss oF soil DEstruCtion AnD rivEr FlooDs
D．thE ExtrAorDinArily rApiD growth oF populAtion