What can result from reduced or blocked blood supply to the brain?

Reduced or blocked blood supply to the brain can lead to a stroke, which occurs when the flow of oxygen-rich blood is disrupted, either due to a blockage in an artery (ischemic stroke) or due to bleeding (hemorrhagic stroke). The brain cells begin to die from lack of oxygen and nutrients, which can result in various neurological impairments and can affect movement, speech, and various cognitive functions.

In the context of the other options, a heart attack involves the interruption of blood flow to the heart muscle and is unrelated to brain activity. Kidney failure pertains to impaired kidney function and is not directly connected to blood supply issues in the brain. A pulmonary embolism involves a blood clot obstructing blood flow to the lungs, which is a separate condition not impacting brain circulation. Therefore, among the options provided, stroke clearly stands out as the condition resulting from reduced or blocked blood supply specifically in the brain.