Question

Four groups of students, in different parts of the world, are investigating the reason why the shape of the moon changes from time to time. If the results of their investigations are considered valid, they would most likely be

A) complex

B) identical

C) non-testable

D) inconsistent

Answer 1

In order for the results of an experiment to be "valid,"
the results must be identical.

What that means is that every time we do the same experiment,
we should get the same results.