Upon close inspection of movement in annelids and nematodes, you would notice an obvious difference. Nematodes tend to wriggle back and forth, while annelids tend to contract along their length as their girth swells and then thin out as they stretch. What anatomical feature explains this type of movement? Select one: a. The annelids possess longitudinal muscle fibers that the nematodes lack. b. The nematodes lack circular muscle fibers. c. Nematodes lack a coelom. d. Annelids have a highly specialized nervous system capable of more complex movements.