Given a scientific question, generate a correct answer to it.

[Q]: For skeletal development, the most common template is what?
[A]: cartilage

[Q]: What contains more calcium than any other organ?
[A]: bones

[Q]: What is the part of the cardiovascular system that carries oxygen-rich blood away from the heart, to the body, and returns oxygen-poor blood back to the heart?
[A]:
systemic circulation