For 10 points, name this phylum whose members include C. elegans, a phylum of roundworms.
An organism from this phylum has been studied for the impact that EGL-1 has on the CED-3 protease, a "killer" protein. In a process first observed in this phylum, Argonaute protein forms part of the RISC complex after Dicer cleaves double-stranded RNAs. There are 959 somatic cells in a model organism from this phylum, the organism in which Andrew Fire and Craig Mello first discovered RNA interference, and also the organism in which Sydney Brenner studied apoptosis. Members of this phylum have a pseudocoel serving as a hydrostatic skeleton. For 10 points, name this phylum whose members include C. elegans, a phylum of roundworms.
An organism from this phylum has been studied for the impact that EGL-1 has on the CED-3 protease, a "killer" protein.
Nematoda [or nematodes; or nemata; prompt on "roundworms" until mentioned"]