1. Nature has an apparently _______ source of plants that can be fruitfully exploited for the herbal cure of many diseases.   indefatigable   inexhaustible   insuperable   iniquitous   insatiable   Hint Hint       2. It is economically beneficial to increase the capacity of an industrial plant when the revenue can be increased without a _______ increase in the cost of production.   compliant   warranted   precarious   controlled   commensurate   Hint       3. After having _______ arguments virtually every other day, the couple agreed that it was best for them to separate.   effulgent   saturnine   assiduous   acerbic   astringent   Hint       4. The students appreciated the professor's _______ style of preparing notes for the lectures because the effort in collecting vital information from various sources truly enhanced their learning.   eclectic   pedestrian   dogmatic   esoteric   pedantic   Hint       5. The _______ allowance he received as a pension forced him to spend the rest of his life in _______.   meager..penury   munificent..conundrum   mendacious..luxury   mundane..malady   magnanimous..austerity   Hint       6. The senior professor was _______ thinker who believed in doing even tedious calculations by hand rather than using a computer.   an insensible   a cogent   an ingenuous   an eclectic   a doctrinaire   Hint       7. The aria was _______ with the tempo changing continuously in a most unpredictable fashion.   capricious   antediluvian   impecunious   abstemious   cacophonous   Hint