Why a commerce student must learn about SDLC and its phases?

Which of these is most responsible for differences between the twentieth century to the twenty-first century?

Im doing this last minute and literally none of my neighbors or people that my dad works with use excel so if anyone could me make up an example

Which of the following tasks is an audio technician most likely to perform while working on a nature documentary? (select all that apply). eliminating potentially distracting background noise adding sound effects making sure the lighting is adequate for a particular scene changing the narration to better match the mood of the documentary