The answer is the endogenous opiate.
The human body naturally produces its own opiates like substances and uses them as neurotransmitters. These substances include endorphins, enkephalins, and dynorphin, often collectively known as endogenous opioids. Endogenous opioids modulate our reactions to painful stimuli.
Explanation:
in the human body or in general sweetie?
Answer:
<em><u>The correct option is D) The two species have a common ancestor</u></em>
Explanation:
In evolutionary studies, homologous structures can be described as structures which are similar in organisms of different species because they had a common ancestor in the past. These structures may not perform the same function but are similar because they arose from a common ancestor. Hence, the bone in a bird's wing can be homologous to a bone in a lizard leg because they have a common ancestor in the past.
Answer: a. endoderm-bone
Explanation: In the context of embryonic development, bone tissue may arise from several precursor cell populations, such as the neural crest (some facial bones), lateral mesoderm (bones of the limbs, among others), and paraxial mesoderm (vertebrae and part of the skull). There is no evidence to suggest that any of the bony structures is derived from the endoderm germ layer.