Do Ocean basins get wider as a result of sea floor spreading?

Answer 1

No, it doesn't because the formation of the Earths crust and the rate of which the sea floor that is shifting away from the ridge is pretty similar. An example is the Mid Atlantic Ridge, the amount of crust that is formed is actually greater than the continental plates pulling away from the ridge. How do we know? The Hawaii Islands are the result of the volcanic activity that is in "overdrive" and the magma is building up quicker than the tectonic plates are pulling apart. It would be impossible for the continents to shift if the rate of which the crust formation was slower than the movement of the continents away from the rift system they were created. It is not possible for them to grow or shrink in size as long as there are weak spots in the Earths crust. However we actually need there to be weak spots in the Earth's crust, according to the most recent studies on how life began, life started deep in the oceans in the ridges that forms the Earths crust, there are huge underwater volcanoes that spew out lava and toxic gasses. There the first single cell organism was formed because of an apparent chemical reaction. There is no life on Mars because it has no weaknesses in it's crust.