Question

______ protects the brain from most viruses that may destroy neurons within the brain.
the blood-brain barrier
hormone therapy
neurocognitive therapy
gene therapy

Explanation:

The blood - brain barrier is a protective structure. It consists of endothelial cells that tightly regulate what substances can pass from the bloodstream into the brain tissue. Hormone therapy involves using hormones to treat various conditions (e.g., hormonal imbalances). Neurocognitive therapy focuses on improving cognitive functions (e.g., memory, attention) through specific exercises. Gene therapy aims to treat genetic disorders by modifying genes. Since the question is about protecting the brain from viruses (a physical barrier - related function), the blood - brain barrier is the correct answer.

Answer:

The blood - brain barrier