[单项选择]Passage Three New research suggests that animals have a much higher level of brainpower than previously thought. If animals do have intelligence, how do scientists measure it Before defining animals’ intelligence, scientists defined what is not intelligence . Instinct is not intelligence. It is a skill programmed into an animal’s brain . Rote conditioning is also not intelligence. Tricks can be learned by repetition, but no real thinking is involved . Scientists believe that insight(顿悟) the ability to use tools , and communication using human language are all effective measures of the mental ability of animals. Scientists define insight as a flash of sudden understanding . When a young gorilla could not reach fruit from a tree , she noticed some boxes scattered about the lawn near the tree . She piled up the boxes , then climbed on them to reach her reward . The gorilla’s insight allowed her to solve a new problem without trial and error. The ability to use to
A. a sign of intelligence
B. a sign of instinct
C. learned through training
D. programmed in their brain at birth