the bottom of the buildings would stand. unless the building was without nuts and bolts like a jenga house then yes it would fall all the way. only that section of the building shouldve been destroyed where they planes hit.
you can take a bat to a concrete chimney and wack at it the bricks on the bottom will still be there. STEEL reinforcements DONT collapse you have to CUT them in many places to dislodge them
just goes to show to buy into anything the media sells you from supplements, to religion, medicine, to what is going on in the world. just use your intuition on what you think is right to do for you and others