Will the section of a worm affect regeneration ?

Earthworms can regenerate but to the extent that they can regenerate is dependent on species. Generally when an earthworm is cut in half, only one half will be able to regenerate (the half with the head attached) while the other half dies. Also, if the earthworm is cut to close to the head (greater loss of segments) then it will not be able to regenerate and both halves will die.