Each sentence below has one or two blanks, each blank indicating that something has been omitted Beneath the sentence ate five, words or sets of words labeled A through E. Choose the word or set of words that, when inserted in the sentence, best fits the meaning of the sentence as a whole. 

Example: Medieval kingdoms did not become constitutional republics overnight; on the contrary, the change was ----. 

{A) unpopular (B) unexpected (C) advantageous (D) sufficient (E) gradual

 Acid_ rain is damaging lakes in ---- way, causing the virtually unnoticed ---- of these aquatic ecosystems. 

(A) a manifest .. eradication (B) a nefarious .. polarization (C) an insidious .. d~struction (D) a methodical .. amalgamation (E) an obvious .. stagnation