1. The vertebrae, collectively, make up a more complex structure, which is called what?
From Quiz Quiz and Crossword Combo #2: Body Parts
Answer:
Spine
There are thirty-three vertebrae in a human's vertebral column. The upper twenty-four articulate and each have inter-vertebral discs between these bones, but the lower nine are fused in adults (five in the sacrum and four in the coccyx).
The spine is divided into regions called the cervical spine, thoracic spine, lumbar spine, sacrum and coccyx. There are seven cervical vertebrae, twelve thoracic vertebrae and five lumbar vertebrae. The number of these in the cervical region is only rarely different in mammals, with the exceptions being the two sloth genera and the manatee genus. All other mammals have seven cervical vertebrae, even the giraffe but those seven vertebrae are very tall - up to 25cm.
In other vertebrates, the number of cervical vertebrae can range from one cervical vertebra in amphibians, to 25 in swans.
With lower articulating vertebrae, those attached to the ribs are called thoracic vertebrae, while those without ribs attached, are called lumbar vertebrae.