AP BIOLOGY

Detailed explanation-1: -Nephridia. Many aquatic and terrestrial invertebrates use the nephridia as excretory organs. They are tubular or branched structures in contact with the internal body fluids on one side and open to the environment on the other side.

Detailed explanation-2: -Annelids have nephridia as an excretory organ. Thus, the correct answer here is (D) Annelids. In earthworm, the nephridia are generally grouped in pairs throughout the segment of the worm’s body.

Detailed explanation-3: -In earthworms, excretion was done by nephridia. These nephridia contain absorption walls for the absorption of essential for absorbing nutrients. They also have ciliated tubules which push the waste out of the body. Through the means of nephridia, waste is discarded out of the body from the body cavity.

Detailed explanation-4: -Excretory organs of earthworm is pair of nephridia in almost all segments, they excrete the waste through a pair of pores in each segment.