How do i comment on answers? there's one answer i'm confused about but i don't know how to comment on it

Mariah was working on a multimedia presentation that included both video and audio files. the file was huge, and she wanted to send it to her coworker in another office. she needed to reduce the size of the file so that it could be transmitted faster. the utility she used to do this was

20 points archie wants to use a reflector as he photographs a newlywed couple. what would he consider in his choice? a. shadow and sunny b. homemade and professional c. lamps and boards d. incident and reflected e. neutral density and enhancement

What are "open-loop" and "closed-loop" systems