PFD
Dear PFD, this is my last message about this question as you're just avoiding the point. YOU posted a question saying "for the FMS to control", not me, not you, not "I'll just manage the throttles", just THE FMS. So, please stick to rule #1 of these stupid exams and RTFQ. In case you've already read TFQ, please tell us how is it possible for THE FMS to control climb, cruise and descent without controlling the engines.
And again, on your beloved 737 changes in pitch are just a consequence of the AP trying to correct the vertical speed it sensed, changing the elevator deflection to regain a suitable vertical speed to reach the target altitude. And no, you don't change elev defl to chase a target pitch angle, you do it to increase/decrease AoA and the Vspeed. You'd be able to finish a mechanics of flight course without even mentioning the pitch angle, it's quite irrelevant.