Carbon-14, or 14C , has a half-life of 5,730 years. It is constantly being created in the atmosphere though collisions between cosmic particles and atmospheric nitrogen. Because of this, living plants and animals constantly exchange amounts of 14C with the environment. When the plant or animal dies, it no longer absorbs 14C, and the amount left in it decreases due to radioactive decay. The age of organic materials can then be determined by measuring the activity of 14C decay, a process known as radiocarbon dating. Suppose an archaeologist finds an ancient firepit containing partially consumed firewood, and the 14C content of the wood is only 28.8% that of an equal carbon sample from a present-day tree. What is the age of the wood (in yr)?

answer: the direction of the wind is expressed as the direction from which the wind is blowing. for example, easterly winds blow from east to west, while westerly winds blow from west to east.

explanation:

it takes about 30 days for it to break down

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

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bacteria that live on the ocean floor are sustained by phytoplankton. phytoplankton, microscopic marine photosynthetic organisms, have a vastly significant role to play not only in the marine food web of which they’re part of, but also on a more global scale. despite their infinitely small size in comparison to other marine organisms, these tiny creatures occupy an immensely important ecological niche: they are the foundation of the marine food web, and as primary producers, play key roles in supporting all other organisms in the marine environment, as well as in the regulation of the earth’s climate through the sequestration of carbon, oxygen production, and other related processes. phytoplankton account for roughly half of all global primary productivity; therefore, their significance extends far beyond the marine environment alone. there is an intriguing sense of irony in the realization that these tiny living beings that often live out their existence unnoticed and undetected by the rest of the world, have such a far-reaching impact on the lives of virtually all other living organisms on the planet, particularly on those in the marine environment. the world that we have become accustomed to has been and is continuously shaped by the workings of these miniscule yet vital “plants of the sea”.

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