AP Psychology Practice Test 2025 - Free AP Psychology Practice Questions and Study Guide

The concept of brain plasticity refers to the brain's ability to change and adapt in response to experience, learning, or injury. Early childhood is a critical period for brain development involving significant reorganization, which allows the brain to recover from damage more effectively than in adulthood. This reorganization can involve the formation of new neural connections and the strengthening or weakening of existing pathways, showcasing the brain's capability to adapt and compensate for lost functions.

In contrast to this concept, the other options present notions that do not align with the principles of brain plasticity. The idea of an unchanging structure suggests that the brain does not adapt or reorganize, while a static nature in adults implies a lack of flexibility and adaptability over time. Furthermore, the idea of a fixed number of neurons contradicts the evidence that neurogenesis, or the creation of new neurons, can occur, particularly in certain areas of the adult brain. This reinforces the dynamic nature of the brain, especially in its ability to recover and reorganize after experiences or injuries.