Answer:
For early earth, it was filled with loads of oxygen and could kill humans if they breathed the oxygen that was in the air about 100 million years ago. This massive amount of oxygen cause massive creatures like the dinosaurs to exist. Current earth has an atmosphere with not too much oxygen.
Explanation:
brainliest
Answer:
True.
Explanation:
Enkephalins and endorphins are endogenous peptides while morphine is an exogenous peptide.
Enkephalins and endorphins are powerful analgesics 18 to 500 times more than morphine. Hence, morphine is less analgesic than enkephalins and endorphins.
Enkephalins and endorphins act on the mu, kappa , delta receptors and morphine also acts on the same receptors. All of them has same effects on the body.
Hence, Enkephalins and endorphins are peptides that act like morphine.
The contractions of the heart is what creates out blood to pulse through out body and is the basis of our blood pressure; which means this statement is TRUE.
The systolic number (top) of the blood pressure is our heart physically pushing the blood out of the heart and to the rest of the body.
The diastolic number (bottom) of the blood pressure our heart at rest when it has just finished with one pump.
Answer:
Arteries carry oxygenated blood away from the heart. Veins carry the blood back to the heart. Veins contain valves that ensure blood flows in only one direction. Arteries don’t require valves because pressure from the heart is so strong that blood is only able to flow in one direction.
Explanation:
