~Hello there!
Your question: The core of a city, which is primarily based on commercial activity, is called the ____________.
Your answer: The core of a city, which is primarily based on commercial activity, is called the central business district.
Hope this helps! :3
There's a calculator in this planet earth just use that. It's easy
Scientists mapped the magnetic polarity of ocean floor on both sides of the ridge. They found that the pattern of strips of rock with the same polarity matched on both sides of the ridge. This showed that the ocean floor moves away from mid-ocean ridges as new rock forms.