The FREQUENCY of light remains unchanged once it leaves the source.
Since there are no choices, then this question calls for open-ended answers. Facts-based science must have proven underlying laws that support inferences such as Coulomb's Law, Kinetic Theory of Matter and many more. On the other hand, examples of science that focus on personal belief is philosophy. This depends on the perspective of known philosophers. An example would be Sigmund Freud who proposed the theory of 3 personalities. Although it is more on personal beliefs, this is used as a foundation in the study of psychology.
A barometer is used to measure air pressure!
The answer is reflection.
The drawing is simple but illustrates the concept beautifully.
The answer is slightly left and slightly right of the curved end of the horseshoe.
