What two pieces of information would researchers need to have in order to calculate the rate of plate motion for seafloor spreading?

-distance from the rift and age of seafloor sample
-type of rock and distance from the rift
-age of the continent and depth of the water
-age of the seafloor sample and age of the continent

The distance a car travels between the time the driver decides to stop the car and the time the driver puts on brakes is called the reaction distance. how does the reaction distance change with speed? a.reaction distance decreases with with speed b.reaction distance stays the same with speed c.reaction distance increases with speed. d.there is not enough information to answer the question