Due in great part to its characteristic of having a fixed number of cells in the adult, Caenorhabditis elegans has become an important model research organism in developmental biology. To which phylum does C. elegans belong?

Platyhelminthes

Annelida

Arthropoda

Nemertea

Nematoda

Phylum Nematoda

Explanation:

Caenorhabditis. elegans is a free-living transparent nematode about 1 mm in length.

C. elegans is a nematode-a member of the phylum Nematoda:

Nematoda.

The roundworms and threadworms, a phylum of smooth-skinned, unsegmented worms with a long cylindrical body shape tapered at the ends; includes free-living and parasitic forms both aquatic and terrestrial.

C. elegans is a non-hazardous, non-infectious, non-pathogenic, non-parasitic organism. It is small, growing to about 1 mm in length, and lives in the soil-especially rotting vegetation-in many parts of the world, where it survives by feeding on microbes such as bacteria. It is of no economic importance to man.