Instructions: You are given a passage. You need to construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) its answer is the whole paragraph. Avoid creating questions that can be answered correctly without actually understanding the paragraph.
Input: The sky appears blue because the gases(mainly nitrogen and oxygen) present in our atmosphere vibrate at a specific frequency.  From the light that we can see, ie.. blue, green, red, yellow...etc, the the higher frequency colors are absorbed more by the atmosphere than the lower frequency(actually they're scattered, they still make it to us but indirectly whereas the yellowish color of the sun is more direct).  So blue, green, and violet(violet having the shortest wavelength) are absorbed by the atmosphere, while red, yellow and orange are allowed through.   The color of blue that we perceive the sky varies from day to day based on the content of gases present and the frequency that they vibrate.  It works the same way as light passing through a blue balloon, except in this case the balloon is our atmosphere.
Output:
why is the sky blue?