Answer:
Excel is mostly used for data storage. It also more or less has its own programming language within it for automation of data transfer and storage. It's used in a grid layout or what you'd see as a sheet.
I have taken IBCA (Intro to Business Computer Applications) but I'm surprised that you're taking excel in IBCA, perhaps just the basics I'm assuming. Completing IBCA should get you Microsoft certifications in Word and BCA will get you certifications in Powerpoint and Excel. If you pass of course.