Sal had a severe stroke that left him unable to talk for a year. however, during the second year, he gradually regained his ability to speak. what is the most probable explanation for what happened?

Neurogenesis

Explanation: after a stroke, the brain has the ability to heal itself.

In a stroke, a blood vessel is blocked or has a rupture, so the blood can't reach some areas of the brain. Since the neurons don't have blood, they die and this part of the brain, and also the nerve cells, get damaged.

However, the brain can regenerate these brain cells. It is a process called Neurogenesis, and it is basically a process of creating new connections. This process can months or years, depending on the severity of the damage.  

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