Explanation:
D
Roundworms are also known as Nematodes belongs to of the phylum Nematoda, and more than half of the species that have been found are parasites of humans, animals, and even plants.
Early Egyptian physicians between 1553 and $1550 \mathrm{BC}$ noted the existence of the Guinea worm. Dracunculus medinensis, which was later identified by a German Egyptologist in 1820. This huge, thin, and thread-like nematode can grow up to 1 meter long.