Which characteristic of the reptilian brain affects its structure?

The characteristic of the reptilian brain that affects its structure is its simple structure with fewer folds. This simplicity is a defining feature of reptilian brains, distinguishing them from the more complex brains of mammals. The reptilian brain primarily consists of the brainstem and the basal ganglia, which control basic survival functions and instincts such as feeding, mating, and aggression.

The fewer folds indicate a less complex organization in comparison to the highly convoluted brains of mammals, which have many gyri and sulci that increase surface area and allow for more advanced functions like reasoning and emotional regulation. This simplicity in structure relates directly to the evolutionary adaptations of reptiles, focusing on essential life-sustaining processes rather than complex behaviors.

Components such as the reptilian limbic system also show a more primitive organization, emphasizing instinctual behavior over cognitive processing, further underscoring the significance of its simpler structure in comparison to other, more complex brains.