Answer:
Plants and animals assimilate carbon-14 from carbon dioxide throughout their life. When they die, they stop exchanging carbon with the biosphere and their carbon-14 content begins to decrease at a rate determined by the law of radioactive decay.
Radiocarbon dating is basically a method designed to measure residual radioactivity.
Explanation:
Carbon-14 is a weakly radioactive carbon isotope; It is also known as radiocarbon, and is an isotopic stopwatch.
Radiocarbon dating is only applicable to organic materials and some inorganic materials (not applicable to metals).
Proportional gas counting, liquid scintillation counting, and accelerator mass spectrometry are the three main methods of radiocarbon dating.
The radiocarbon, or carbon-14, is an isotope of the carbon element that is unstable and weakly radioactive. The stable isotopes are carbon-12 and carbon-13.
Carbon 14 is continuously formed in the upper atmosphere by the effect of cosmic ray neutrons on nitrogen-14 atoms, rapidly oxidizing in the air to form carbon dioxide and entering the global carbon cycle.
Accelerator mass spectrometry (AMS) is a modern method of radiocarbon dating that is considered the most efficient way to measure the radiocarbon content of a sample. In this method, the content of carbon-14 is measured directly in relation to carbon-12 and carbon-13 present. The method does not take into account beta particles, but the number of carbon atoms present in the sample and the proportion of the isotopes.
Answer:
<h2>92%</h2>
Explanation:
When glucose is converted to ethanol by yeast, one mole of glucose is converted into two moles of ethanol and two moles of carbon dioxide,
and this process produce two moles of ATP.
C6H12O6 → 2 C2H5OH + 2 CO2
When glucose is converted to ethanol by yeast (as in the production of beer) 92% of the chemical energy that was originally stored in glucose still remains in the end product, ethanol, that is produced.
The correct answer is d. morula.
<span>
A morula is a stage in early development, formed 3–4 days after fertilization. It is a 16-cell mass which forms a solid ball contained within the zona pellucida. A morula develops into a blastocyst.</span>
The main function of environmental policy is protecting a society's natural resources. These policies provide necessary measures to make sure all the resources remain available to everyone. The main function of environmental policy is protecting a society's natural resources.
Answer:
<h2>
Gastrin: stomach,
</h2><h2>
CCK- SI,
</h2><h2>
Insulin- pancreas,
</h2><h2>
Glucagon-pancreas. etc</h2>
Explanation:
1. Gastrin: secreted by stomach stimulating activity of the stomach
,
2. CCK: secreted by SI stimulating secretion of pancreatic enzymes; contraction of gallbladder and pyloric sphincter and inhibitory effects on stomach
3. Secretin: secreted by SI if material entering SI is acidic, triggering secretion of HCO₃-
.
4. Insulin: produced by beta-cells of pancreas and
stimulates storage of glucose in liver and muscle and it causes re-uptake of glucose when blood-sugar is high, lowering blood sugar
5. Glucagon- produced by alpha-cells of pancreas and
it stimulates release of glucose from liver when blood-sugar is low, and results in raising blood sugar.
