Nerf blaster disassembly

Hello! I recently had to disassemble and reassemble a nerf blaster (still don’t understand what half the pieces do) in my “how things work” class and my follow up assignment is to 1) provide a high level functional description as well as 2) describe the component systems of the disassembled blaster. What is the difference between writing a high level functional description and describing the component systems of the disassembled blaster? I’m finding myself writing two really repetitive paragraphs about what pieces do what. 

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