How could you determine if a specimen was a flatworm or a le

How could you determine if a specimen was a flatworm or a leech (by looking at it)?

Solution

flatworm comes under Platyhelminthes- bilateral symmetry with no coelom. (Acoelomates)

leech comes under annelida- bilaterlal symmetry with true coelom. (Coelomates) Their body surface is distinctly marked out into segments or metameres, that is a differentiating feature between flatworms and leech.