Practice question

Adult lophophorate digestive tract architecture uniformly reflects constraints of sessile suspension feeding producing characteristic U-shaped gut where mouth opens within tentacular crown allowing immediate capture of filtered particles, while intestine descends into trunk, loops 180 degrees and ascends so anus opens outside lophophore ring near mouth but separated from inhalant current. In phoronids, brachiopods and ectoprocts mouth and anus both anterior near base of lophophore, intestine forming descending and ascending limbs. Arrangement permits simultaneous feeding and egestion without contaminating filtered water, maintains compact body plan inside tube or shell, contrasting with straight gut of errant worms.