It is not profitable; the poor don't have a big money surplus and the firms would not make a lot of profit. Instead, they claim, the firms would rather tend to the rich.
Answer:
visible light (wavelength between 0.4 and 0.8 micrometre)
ultraviolet light (wavelength shorter than 0.4 micrometre)
infrared radiation (wavelengths longer than 0.8 micrometre)
Probably when they're aging or Young Adults
She is exposed to an environment in which utilizing and practicing the language is a necessity when living in the particular society. By being exposed to such an environment allows her to become more used to the language, therefore her ability to pick up the language quickly is increased exponentially.
