Do we as a nation spend too much time on the issue of diversity? Or do we spend too little time on it?

The answer is the second choice,  the rates at which criminals are rehabilitated into society after their sentencing

Are you referring to tectonic plates?

This is called visual imagery. it is a memorization technique wherein an idea or a term is associated with an image, this in remembering ideas, especially as humans are very visual learners. this is also why visual aids a lot for memory retention.