Response to a response

This is the second time it has been pointed out to me that I open my fourth paragraph with the same sentence I use to end my first. I did that intentionally for effect, but perhaps such an effect is more effective in a speech and I shouldn't use it here.
In the fourth paragraph, my use of "called back" twice in such close proximity just needs to be changed. I missed that in my first edit, which is unusual, because that is something I tend to notice and try to change.
The comment about most people not knowing what open or closed posture are is definitely true. I'm not sure, however, if I should just say, "switching postures," because that also sounds confusing. Maybe it just sounds that way to me, but I'll have to look into a way to make it better.
The bit about my needing a more definite conclusion is definitely true. I just kind of left the essay, which kind of drops the effect of the whole thing. It looks like I need to make my point a little clearer.