Answer:
The answer is Pelvic.
Explanation:
The following are groups of vertebrae: cervical, thoracic, lumbar. The pelvis is not part of this group. The pelvis is located at the bottom of the trunk. It is a funnel-shaped cavity (musculoskeletal) that narrows downward, limited by the sacral bone, the coccyx and the coxals, thus forming the pelvic girdle and the muscles of the lower abdominal wall and the peritoneum.
Abiotic are things that never came alive like dirt for example and biotic are living things like worms. Abiotic also includes weather. abotic and biotic inflhence the population size by providing reasources basically.