Why is seeing the light in our pictures important?

 Because it will give you the lighting you want (the right lighting) you can give a photo certain emotions by changing the light. Also if you don't pay attention to it,  it may affect the picture you are taking negatively such as the color the clearness, etc.

Concerto grosso was composed during the classical era. (sorry if i misspelt the name)

Opposition of two melodic ideas is the  right answer