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: The following statements <em>comparing respiration in fish and in mammals</em> is correct:
- The movement of the respiratory medium in mammals is bidirectional, but in fish it is unidirectional.
Explanation:
<u>Breathing </u>is the process by which living beings <em>exchange gases</em> with the external environment. It consists of the <u>entry of oxygen</u> into the body of a living being and the <u>exit of carbon dioxide</u> from it .
Active ventilation occurs if the animal produces the currents (of air or water) that flow to and from its respiratory membranes. It can be :
- Unidirectional. (air or water is pumped onto the respiratory membrane in only one direction).
- Bidirectional. (air or water is transported to the respiratory membrane and moves away from it through the same route like in the mammals).
Answer:
Fossil fuels produce energy when used
Explanation:
when something combusts or is used it produces energt
Answer:Rocky intertidal
Explanation: they provide them shelter because the rock acts as a media(surface) in which glue to hold or stick to organism. The glue been secreted by seeweed is an adaptation(survival) mechanism they have to Rocky intertidal
