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How does blood circulate through the heart?

De-oxygenated blood in the body returns to the right atrium of the heart through the superior and inferior vena cava. This blood is pumped through to the right ventricle , the tricuspid valves prevent any ba...
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Answered by Clarisse B. • Science tutor
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Which chamber of the human heart pumps blood towards the lungs?

The right ventricle pumps blood towards the human heart.
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Answered by Alice W. • Science tutor
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The mass of a balloon is 0.02g before it is filled with air. After it is blown up with air the mass is 0.04g. Assuming oxygen makes up 21% of air, calculate the number of moles of oxygen in the balloon.

Mass of oxygen in balloon = 0.02 x 0.21 Mr (O2) = 16 x 2 = 32 Moles = mass / Mr = (0.02 x 0.21) / 32 = 1.31 x 10^4 moles Or 0.000131 moles
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Answered by Alice W. • Science tutor
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What are the stages of the Carbon Cycle? How are fossil fuels affecting CO2 levels?

Stage one: Carbon enters the atmosphere by - respiration in organisms (e.g. animals breathing) - combustion (e.g. burning of fossil fuels/ wood) - decomposition and decay (microorganisms respiration) Stage t...
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Answered by Rebecca A. • Science tutor
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How has the camel [shown, with summarising information] adapted to survive the desert? Briefly explain adaptation by natural selection.

Answers can include: lomg eyelashes and closing nostrils to protect from sand in the wind, large eyebrow ridge and thick eyebrows to protect from sun, thick fur to contain heat during cold nights, sandy colo...
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Answered by Ruth H. • Science tutor
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