why is it that these days alot of defense and offensive linemen stand up?

Question

i watched a couple of college football games and some of the offensive linemen stand up, and as well as the defense, specifically defensive ends, why is this?

Answer 1

Usually when an offensive lineman is standing at the time of the snap, the play is a pass. Standing allows them all to see more and react to the rush.
On defense, the central linemen will usually be in a 3-point stance. You may also see the outside linebackers down. But defensive ends will do either. Sometimes it is a preference, other times they will disguise their intent by standing. Also being up allows them to do more than rush...DE's are also responsible for outside containment and to shadow the RB out of the backfield.