Technically a gigabyte is 1000 megabyte. Megabytes are 1000 kilobytes and kilobytes are 1000 bytes. Which are all proper metric units but sadly don’t make any sense. So datasystem manufactures and computer generally calculate with their proper counterparts that you mentions gibibyte mebibyte and kibibyte which sre actualy 1024 of their previous ones. Small but crucial difference.

Not sure anymore. The lesson we were taught just basically said that it damages your lunge if you breath in too much. There were some other interesting thins in that lesson. Basically that cars release not only co2 but also pure c into the air which binds o3 elements into co2 and o2. Which is why in cities and region with more traffic less o3 can be found. O3 is also more common and really sunny days. But please take this with a grain of doubt as this was some years ago.

O3 is again not good for us. Not breathe it and die but it attacks your lungs if you inhale too much.