Question about meso compounds

Why aren’t these all Meso compounds?? They all have a plane of symmetry?! (Btw this was after I did an anti addition, so I’m trying to figure out why the non-meso ones wdnt have an enantiomer but I can’t see why some are not meso in the first place)

Thank you so much :)

Why aren’t these all Meso compounds?? They all have a plane of symmetry?! (Btw this was after I did an anti addition, so I’m trying to figure out why the non-meso ones wdnt have an enantiomer but I can’t see why some are not meso in the first place)

Thank you so much :)