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Alona [7]
4 years ago
13

Describe natural selection- when does natural selection occur?

Biology
1 answer:
sashaice [31]4 years ago
7 0

Answer:

The process whereby organisms better adapted to their environment tend to survive and produce more offspring. The theory of its action was first fully expounded by Charles Darwin, and it is now regarded as be the main process that brings about evolution.

Four conditions are needed for natural selection to occur: reproduction, heredity, variation in fitness or organisms, variation in individual characters among members of the population. If they are met, natural selection automatically results.

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Where does the gastric juice go
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It goes to the pancreas
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4 years ago
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The USGS assessed mining in Afghanistan and found that:
Ghella [55]

Mining in Afghanistan is controlled by the Ministry of Mines and Petroleum, which is headquartered in Kabul with regional offices in other parts of the country. Afghanistan has over 1,400 mineral fields,[1][2][3] containing barite, chromite, coal, copper, gold, iron ore, lead, natural gas, petroleum, precious and semi-precious stones, salt, sulfur, talc, and zinc, among many other minerals.[1][4] Gemstones include high-quality emerald, lapis lazuli, red garnet and ruby. According to a joint study by The Pentagon and the United States Geological Survey, Afghanistan has an estimated US$3 trillion[5] of untapped minerals.

There are six lapis mines in Afghanistan, the largest being located in Badakhshan province. There are around 12 copper mines in the country, including the Aynak copper deposit located in Logar province.[6] Afghanistan's significance from an energy standpoint stems from its geographical position as a transit route for oil, natural gas, and electricity exports from Central Asia to South Asia and the Arabian Sea. This potential includes the construction of the Trans-Afghanistan Pipeline gas pipeline.[7] The first Afghan oil production began in late 2012.[8]

The United States Geological Survey (USGS) and the British geological survey were doing resource estimation work in the country. Prior to that work, Afghanistan's exploration activity had been conducted by geologists from the Soviet Union who left good-quality geologic records that indicate significant mineral potential. Resource development would require improvements in the infrastructure and security in Afghanistan. The government had awarded contracts to develop the Aynak copper project and the Hajigak iron ore project; in addition, the government could offer tenders for new exploration, including exploration of copper at Balkhab, gold at Badakhshan, gemstones and lithium at nuristan, and oil and gas at sheberghan.

The Ministry of Mines drew up its first business reform plan in a bid to create a more accountable and transparent mining industry. Afghanistan joined the Extractive Industries Transparency Initiative as a candidate country. It was expected that after 5 years, the contribution of royalties from mineral production to the revenues of the government would be at least $1.2 billion per year, and that after 15 years, the contribution would increase to $3.5 billion per year.[11] Afghanistan has no local ownership requirements and its Constitution does not allow for nationalization. The 20% corporate tax rate was the lowest in the region.

Afghanistan's mining industry was at a primitive artisanal stage of development; the operations were all low scale and output was supplied to local and regional markets. The government considered development of the country's mineral resources to be a priority for economic growth, including development of the industrial mineral resources (such as gravel, sand, and limestone for cement) for use by the domestic construction industry. Investment in infrastructure and transportation projects for mining was a critical aspect of developing the mining industry.

The government completed Afghanistan's first railway with an investment of $170 million in 2010. The 76-kilometer (km) route link Mazar-i-Sharif to the extensive rail networks in Uzbekistan. The new route would allow Afghan exporters to transport minerals and other goods into Europe. China Metallurgical Group Corporation (MCC) is building a railroad to transport copper ore in Afghanistan from Logar to Kabul.

Owing to the lack of mineral production data reported by the miners, information about Afghanistan's mining activities was not readily available, but they appeared to be limited in scope. Production of Barite was estimated by the USGS to be about 2,000 metric tons; chromite, 6,000 tons; and natural gas liquids, 45,000 barrels. In the process of reconstruction and infrastructure development, output of construction minerals was estimated to have increased to meet the domestic requirements. Production of cement increased by 13% compared with that of 2009.

4 0
4 years ago
When an organism is alive, the ratio of C-14 to C-12 ___ over time.
pashok25 [27]
The ratio of c-14 to c-12 is consistent over time.
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4 years ago
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Why do you think it is important to take an average resting heart rate versus relying on one value alone? what are some factors
Marina CMI [18]
2) One value might be distorted; for example it is usual that a heard rate right after sitting down can be higher than the rest rate. Other factors that might affect this is the rate of breathing, exercise. We also have that some bleeding can affect this. Finally, the point that you use to measure the heart rate can also be important in making correct measurements.
1)Taking multiple heart rates leads to more reliable results because you can use the mean and not a single value that might be far off it. You avoid thus the effects of the factors above that happen often enough so that we would appear to be ill many times when we are perfectly healthy; In scientific terms, there is some variance in measurements and that is fine.
3) Even if their resting heart rates are the same, they can react differently to stress. One reason is having low iron in your blood; it is essential for transferring oxygen in your blood and thus it is esssential when one does gymnastics. A person with low iron will have a higher pulse to accomodate his cells' needs for oxygen. The same applies to persons with breathing problems or different fitness (even if the resting heart rate is the same). Also, there could be the case that genetically one has less mitochondria and this also affects oxygen and blood needs in exercise.
4) The average rate for adults is 60-100 beats per minute. While this is not abnormal, it is rather high. An examination might be advised to see what leads to such a high bpm rate. If this yields nothing, it could be that due to age and physics reasons this is normal.
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4 years ago
Describe the function of each organ through which food passes as it moves through the digestive tract.
WITCHER [35]
The digestive system is made up hollow organs that consists of the mouth, esophagus, stomach, small intestine, large intestine and anus, sequentially. The supplementary organs are the liver, pancreas and the gall bladder.

The food enters first through the (1) MOUTH where mastication or the mechanical breakdown of food particles takes place. After the food is being swallowed it passes through the (2) ESOPHAGUS which is the conduit between the pharynx and (3) STOMACH which secretes acid and enzymes that chemically breaks down food that is termed as chyme. It comprises 10% of the digestion  and absorption. The chyme or partially digested food goes to the (4) SMALL INTESTINE where 90% of the digestion and absorption takes place. Its main functions is to absorb the nutrients and minerals from the chyme. (5) The LARGE INTESTINE is where the water from the remaining indigestible food matter is being absorbed. It also transmits the useless waste material from the body where it is excreted through the (6) ANUS
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4 years ago
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