Which of the following best describes how the brain operates?

A) It is nicely organized into structures that correspond to specific behavior categories.
B) Researchers are not able to determine exactly how the brain operates.
C) It is not an integrated system.
D) While some brain structures are involved in specific behaviors,they are also involved in other mental phenomena as well.

While some brain structures may be involved in specific behaviors, they are also integrated with other mental phenomena. Therefore, the brain operates as an integrated system where various structures are involved in multiple cognitive and behavioral functions. Option A is incorrect because while the brain has organized structures, they do not necessarily correspond to specific behavior categories. Option B is also incorrect because while there is still much to learn about the brain, researchers have made significant progress in understanding brain function. Option C is incorrect because the brain is an integrated system where different structures work together to produce behavior and mental phenomena.