Why do we need the biological level in addition to the chemical level?

• A. Because certain brain structures appear to be used for particular things
• B. Because brain structures are identical to chemical levels
• C. Because biology cannot explain behavior
• D. Because chemistry is irrelevant to neuroscience

Answer: (A)

The key idea is that brain function comes from both where things happen in the brain and how signals are chemically transmitted within those areas. Certain brain structures seem specialized for specific tasks—language, movement, memory, emotion—so knowing that the brain’s anatomy constrains and enables particular functions helps explain why a behavior occurs. The chemical level explains how neurons communicate and how neurochemical signals modulate those processes inside and between structures. Together, structure tells you what can be done, and chemistry explains how those abilities are regulated and executed. For example, memory relies on the hippocampus (a specific structure), while neurotransmitters and receptors in that region modulate how memories are formed and stored.