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.
They are not aware of each other because usually they are sesperate and don't live together.
Answer:
the life chain of a particular animal
Answer:
Larger ships transport invasive species in their ballast water, while fouling organisms such as barnacles, seaweeds and mussels can move from one location to another by hitching, a ride on a boat, on items you use in the water and even your clothes