This is from SAT subject biology test practice question. The answer it gave me was both chiasmata and centromeres. I can understand they are held by chiasmata but why also centromeres? I looked it up, I didn't find anywhere mentioned that they are held by centromeres also, only synaptonemal complex and chiasmata.
tetrads are truly held by spindle fibers on centromeres too, but isn't the question asking what hold them together? Even without spindle fibers, they can still be held by chiasmata I guess.