511. HOST : PARASITE ::
A. meadow : soil
B. egg : bird
C. medium : bacterium
D. lair : predator
E. kernel : seed

512. SENSITIZATION : ALLERGIC ::
A. immunity : vulnerable
B. habituation : inured
C. invigoration : stimulating
D. sleep : anesthetic
E. disinfection : preventive

513. EUPHEMISM : OFFENSE ::
A. rhetoric : persuasion
B. prevarication : truth
C. metaphor : description
D. repetition : boredom
E. conciliation : appeasement

514. APOLOGIZE : CONTRITE ::
A. aggravate : contemptuous
B. endorse : esteemed
C. extenuate : guilty
D. compliment : impressed
E. rationalize : modest

515. COWARD : CRAVEN ::
A. liar : facetious
B. dupe : gullible
C. commentator : caustic
D. judge : impartial
E. criminal : hostile

516. RENOUNCE : PLEDGE 
A. exculpate : victim
B. desecrate : shrine
C. recriminate : hero
D. redeem : honor
E. rescind : order

517. REQUEST : COMMAND ::
A. propose : stipulate
B. enlist : support
C. relegate : consign
D. volunteer : accept
E. select : reject

518. BLANDISHMENT : COAX ::
A. medal : honor
B. budget : save
C. diary : reminisce
D. concert : play
E. plea : threaten

519. EXORBITANT : MODERATION ::
A. dispassionate : equanimity
B. macabre : interest
C. perfidious : loyalty
D. brilliant : gullibility
E. lavish : extravagance

520. FERTILIZE : GROW ::
A. immunize : resist
B. nourish : enrich
C. heat : burn
D. graft : multiply
E. prune : dwarf