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:
It acts as a weed killer by blocking photosynthesis
Explanation:
Photosynthesis is important to plants because it is their principal form of energy.
When DCMU is introduced to weeds, what it does is to block or slow down the process of photosynthesis. Carbon dioxide fixation is slowed down causing weeds to die off. DCMU strongly slows down photosystem II. When this is done, lipid and protein membranes would get destroyed and the weed cells would begin to dry and shed off
Answer:
The correct answer is "selection favors multiple distinct trait values, and similar individuals tend to mate with each other".
Explanation:
A population with a bimodal distribution are groups of organisms with two major traits or "modes", with practically equal amounts of individuals with these two modes. This type of distributions indicate that the population is not homogenous and that more than one trait is favored in the given circumstances. A bimodal distribution is most likely to evolve when selection favors multiple distinct trait values, and similar individuals tend to mate with each other. In this case natural selection favors more than one value, and due to the individuals with one value tend to mate to each other, only two major traits are favored in the population.
The most surprising thing about the universe is that it we don’t know when it will end and it could end at any point in time. The most surprising fact about our galaxy is that it would take around 26,000 years to get out of it.
By looking for the presence of the germ layers and the primitive gut in the embryo
