why nepridia in earthworm that are basically similar in structure classifiee into three types ? Mention the names of each .

Explanation

Nephridia are the main excretory organs n earthoworms , they are associated with excretiry and osmoregulatory functions the nephridia occcurs in all segement of earthworm except the first two segments the three types of nephidia are found in earthworm according to their locatin .
they are disinguished on the basis of being enteronephric (nirogen waste expelled input) and ( exonephric (nirtogen waste discharged outside directly ).

Septal Nephridla these are present on siders on inter segment septa of the segments starting form 15 th to the last open into interstibne they are enteronephic .
Intergumenatrty Nepherdla these arae attached to lining of the body wall of segment 3 to the last that open on the body surface they are exonephic.
Pharyngeal Nephidle these are present as a three pairded tufts in the in the 4 th 5 th and 6th segments they are also enteronephric .