During embryonic development, the vertebral column is replaced by the notochord.
a. true
b. false

Hello! The answer is false.

It is actually the opposite. The notochord is a primitive axial skeleton, and in humans, it disappears. It eventually becomes part of the vertebral column, which is the backbone that we have today.

Hope this helps!

Morphine and heroin have very similar structures, and they are classified into the group of opioids. All of the opioids, including morphine and heroin lock into endorphin receptors in the central nervous system causing a feeling of intense euphoria.