Choose the most appropriate answer for each question.
Question 1 :
Last spring, the periodical cicadas emerged across eastern North America. Their vast numbers and short above-ground life spans inspired awe and irritation in humans—and ____ for good meals for birds and small mammals.
Question 2 :
whether any of the substances possess addicting properties is very difficult to determine on animals, although efforts are being ____ to study this aspect of the problem on dogs and monkeys.
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