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

A fully developed placenta is made up of a large mass of what?
blood vessels

During the embryonic stage of vertebrates, the notochord develops into what?
backbone

What title is used to describe health professionals who use nonsurgical techniques to help patients with musculoskeletal system problems that involve the bones, muscles, ligaments, tendons, or nervous system?

chiropractor chiropractors

