Answer:
The question means: Why are the important colors on the Argentinian flag blue & white.
If you're actually asking this question, and not what it means, then..
there are a lot of interpretations of the colors' meaning. One is that they represent the sky and the clouds (with the sun symbol in the middle as well.) Another interpretation is that the colors represent the pure Virgin Mary. Yet another is that the colors represent the House of Bourbon.