The given blank can be filled with the production of endorphins.
The endorphins are the hormones, which are responsible for the activation of the opiate receptors in the body. They are the natural pain killers. The activation of the opiate receptors causes the analgesic effects on the body.
These endorphins are secreted in the brain and the nervous system. The effect of the endorphins is similar to that of the morphine.
Answer:
Invertebrates include all animals that lack a backbone, or a vertebral column. All chordites exhibit four characteristics during at least one stage of life: a dorsal, hollow nerve chord; a notochord; a tail that extends beyond the anus; and pharyngeal pouches.
Answer:
I think it's the first option
The Hominind species that is characterized by a vertical forehead is Homo sapien.
Homo sapiens are the species to which all living humans belong. In comparison with other species, the homo sapien species is characterized by a higher and more vertical forehead, a round and gracile cranium, small face and teeth, a prominent chin, and a more slender and elongated post-cranial skeleton.
