The north american and european plates of the
earth’s crust are drifting apart with a relative speed of
about 25 mm/yr. take the speed as constant and find when
the rift between them started to open, to reach a current
width of 2.9 x 10^3 mi.

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?