Answer:
We have learned that refraction occurs as light passes across the boundary between two media. Refraction is merely one of several possible boundary behaviors by which a light wave could behave when it encounters a new medium or an obstacle in its path.
The answer is: Expressive vocabulary
Expressive vocabulary refers to the combination of all the words that a person has acquire throughout his/her life and can be used in various type of situations.
This would include all words in the child vocabulary, starting from the child's written language, spoken language or even the child's manually signed words.
I'm pretty sure its transverse waves
Radar waves are the waves with the lowest energy.