The fact that the galaxies are rotating at about the same velocity from the center to the edge as opposed to faster near the centers is evidence that .. a. there must be more gravity than that calculated from normal Mass
b. they are rotating slower over time
c. dark energy is pulling on them
d. they are measuring the velocities incorrectly ​

what experimental evidence led scientists to change from the previous model to this one?

a few of the positive particles aimed at a gold foil seemed to bounce back.

the colors of light emitted from heated atoms had very specific energies.

experiments with water vapor showed that elements combine in specific proportions.

cathode rays were bent in the same way whenever a magnet was brought near them.