Prostomium is the frontmost part of the earthworm. This is not called a
true segment as it doesn't contain typical organs of an annelida. Peristomium is from where the true segment of the earthworm body starts.
The esophagus of an earthworm is part of the earthworm's digestive tract, between the pharynx and the crop, and it basically just moves the earthworm's food from the pharynx to the crop. It also helps to keep the food from backing up (making the worm barf/throw up).
There are about 30 segments between the prostomium and clitellum of an earthworm. actually this question asked as differently as "How many segments are between the prostomium and clitellum of an earthworm?" see answer for this question.
leeches are sthnakes.
Lecches lost their internal metamery, while polychaetes not.
What is the different between NAS & SAE.
Between what?
The different between sag and surges
In annelids, the group known as clitellates, which includes earthworms and leeches, has lost the septa between coelomic compartments. This loss allows for a more integrated and flexible body plan, facilitating movement and the efficient use of body space for various functions, such as reproduction and locomotion. The absence of these septa contrasts with other annelid groups, such as polychaetes, which retain distinct septa between their coelomic segments.
There is nothing different between them in a real time.
different between sri lanka and cuba
different between organic growth and acquisition
It is thought that annelids were originally animals with two separate sexes, which released ova and sperm into the water via their nephridia.[3] The fertilized eggs develop into trochophore larvae, which live as plankton.[33] Later they sink to the sea-floor and metamorphose into miniature adults: the part of the trochophore between the apical tuft and the prototroch becomes the prostomium (head); a small area round the trochophore's anus becomes the pygidium (tail-piece); a narrow band immediately in front of that becomes the growth zone that produces new segments; and the rest of the trochophore becomes the peristomium (the segment that contains the mouth).[3]