SCIENCE
CIRCULATORY SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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some is cold, some is warm
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some is oxygen, some doesn’t
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some is old, some is new
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some is healthy, some is sick
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Detailed explanation-1: -As blood leaves the heart and is oxygen-rich, it is bright red. When the blood returns to the heart, it has less oxygen. It is still red but will be darker. This darker red appears blue because of how light travels through the skin.
Detailed explanation-2: -Blood is always red. Blood that has been oxygenated (mostly flowing through the arteries) is bright red and blood that has lost its oxygen (mostly flowing through the veins) is dark red. Anyone who has donated blood or had their blood drawn by a nurse can attest that deoxygenated blood is dark red and not blue.
Detailed explanation-3: -But blood actually comes in a variety of colors, including red, blue, green, and purple. This rainbow of colors can be traced to the protein molecules that carry oxygen in the blood. Different proteins produce different colors.
Detailed explanation-4: -They only look blue because when wavelengths of light hit your skin and veins, some light is absorbed, and some reflected back at you. Wavelengths of blue light cannot penetrate skin as well as red light, and more blue wavelengths are reflected back at you than red wavelengths.
Detailed explanation-5: -Deoxygenated blood is darker due to the difference in shape of the red blood cell when oxygen binds to haemoglobin in the blood cell (oxygenated) versus does not bind to it (deoxygenated). Human blood is never blue.