Final answer:
The feature found in Nematoda and not in Mollusca is (c) a cuticle. Both phyla have muscles, a central nervous system, and bilateral symmetry, but only Nematoda possess a collagenous/chitinous cuticle that necessitates molting.
Step-by-step explanation:
The student has posed the question: Which of the following is found in Nematoda and not in Mollusca? The answer is (c) cuticle. Nematodes, which are part of the superphylum Ecdysozoa, have a distinguishing feature which is a collagenous/chitinous cuticle that covers their body. This cuticle requires periodic molting to accommodate growth, which is not found in Mollusca. Mollusca, such as squid and octopi, have muscles, a central nervous system, bilateral symmetry, and do not exhibit radial symmetry, which are characteristics also shared by Nematoda.
Both phyla are bilaterally symmetrical, contain muscle tissue, and have evolved a centralized nervous system. These systems support more complex movements and behaviors when compared to organisms with radial symmetry. While radial symmetry is associated with organisms in a stationary or sessile lifestyle, bilateral symmetry supports active and controlled directional movement. Hence, radial symmetry (e) can be ruled out since it is not a feature present in either Nematoda or Mollusca.