Answer:
A scientific question is usually guided by a hypothesis which can lead to additional questing about the phenomenon (A).
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Explanation:
The air that we breathe is mostly made up of nitrogen (78%). 21% is oxygen which is needed for animals and humans in respiration and 0.03% is carbon dioxide which is needed for plants to make energy in a process called photosynthesis. The bit that is left is made up of rare gases like helium and argon and methane.
<span>dentify the part of a rib and thoracic vertebra indicated by "C." Neck of rib ... Correctly match the term and definition: Forms the posterior hard </span>
Arteries Larger, more muscular and more elastic, carry oxygenated blood from the heart, with the exception of the pulmonary artery. The blood has more pressure from the heart. Veins Under less pressure, so valves are needed. They are less strong than arteries and appear more floppy.
Arteries have thick, elastic, muscular walls whereas veins have thin walls with few elastic fibers. Arteries need these properties to give them the strength and elasticity needed to cope with the high pressure surges of oxygenated blood coming from the heart. Veins carry blood back to your heart from the rest of your body. The pressure of the blood returning to the heart is very low, so the walls of veins are much thinner than arteries.
To learn more about Arteries , here
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