I showed up to the interview dressed to the nines, post double shot latte, and mentally prepped only to be ushered to a hallway lined with chairs and a dozen other potential applicants already waiting their turn. I knew I needed something to make me stand out if I had any chance of securing the job.
Answer 1: At plate boundaries where sea-floor spreading occurs, magma wells up to fill the space created by the plates that are moving apart. Check out this United States Geologic Survey (USGS) educational animation to see visually how it works:
When the rock rises, it pushes the plates apart just a tiny bit each time, and when it meets the ocean water it solidifies, creating new ocean floor. If you were to look at an age map of the Atlantic (link below), you'd see that the youngest floor is closest to the MOR, the oldest floor is distant from the ridge. The oldest seafloor anywhere is in the Pacific, near the Marianas subduction zone -- pretty much as far as you can get from the MOR (a spreading center).