Answer: D. nephridia, a heart, metamerism and, in some cases, jaws.​
Explanation:
Since the organism in Phylum Annelida worms and simple worms seems very common but they have may differences, which are as following:
- Nephridia: Nephridia are the paired excretory organs that occur in the Annelida phylum. They discharge metabolic water from the body, I is not present in simple worms as roundworms.
- Heart: aortic arches are present in earthworms (Annelida), which pump blood out into the network of vessels that run in a circuit through the body.
- Metamerism: Metarism defines the segmented body characteristic of annelids which is not found in other simple worms. It is easily visisble in earthworms.
Hence, the correct answer is D.
