D.) a unicellular organism that has a simple structure and is commonly found in human intestines.
Answer:
C) lumbar vertebrae; short, flat spinous processes
Explanation:
The Lumbar Vertebrae are bigger and stronger than vertebral bodies in certain positions.
The vertebral bodies and disks bares majority of the body weight of the body. The lamina, facets and spinous process are basic components of the posterior materials that assist in guiding the movement of the vertebrae and as a coverage or protective shelter for the spinal cord.
The spinous process are SHORT and STURDY (FLAT) in the Lumbar Vertebrae. Hence, this explain why it is often referred to as "Hatchet-Shaped".
The attached image as red dots meant to point to the spinous process in the Lumbar Vertebrae.
Because it is the evolution ary process that the caterpillars is designed to go through according to this species.