How did watson and crick determine base pairing they analyzed the work of phoebus levene. they used chargaff's rule to fit the bases together. they broke the hydrogen bond. they observed the pairing under a microscope.

The answer is B They used Chargaff's rule

Explanation:

Hope this helps! :P

a mid-ocean ridge or mid-oceanic ridge is an underwater mountain range, formed by plate tectonics. this uplifting of the ocean floor occurs when convection currents rise in the mantle beneath the oceanic crust and create magma where two tectonic plates meet at a divergent boundary.a geomagnetic reversal is a change in a planet's magnetic field such that the positions of magnetic north and magnetic south are interchanged.