The idea that Earth’s lithosphere is divided into large, moving sections is called the <u>plate tectonics theory</u>.
Explanation:
The theory of plate tectonics assumes that the lithosphere is divided into large, limitedly stable segments, formed by rigid rock, called plates. These plates extend throughout the globe. There are seven plates in total, such as the Pacific Plate, the Coconuts Plate, etc. These plates reach depths between 100 and 200 km. Each plate runs horizontally with respect to its neighbor. Approximately seventy percent of the area covered by the plates are the oceans, such as the Pacific, the Atlantic or the Indian Ocean.
Answer: Where would the blood come from if there were a blockage just posterior to the middle cerebral artery on the left? If blood could not get to the middle cerebral artery through the posterior circulation, the blood would flow around the circle of Willis to reach that artery from an anterior vessel.