Question: Scientists have measured the rate of growth of the Atlantic Ocean basin to be about 2 to 3 cm per year. This type of activity coincides with the formation of ridges on the ocean floor. What is the most likely cause of this activity?

  Options: 
 A. erosion from tidal action
 B. the deposition of sediment
 C. the flow of continental basalt
 D. movement from tectonic plates 
Answer: D