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写结构式:3、乙醚

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微生物准性杂交育种的基本步骤是什么

Trainers reward the monkeys by using positive reinforcement, such as food, drink, praise, and ____(感情) .

For example, compared with humans, dogs are “far superior at tracking down odors,” says Marian Bailey, an animal ____(行为科学家) at Henderson State University in Arkansas.

“Dogs love to retrieve objects so the towel becomes a reward,” says Morris Berkowitz, who heads up a ____(犬的) drug-sniffing program in New York.

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