Typically, the narrator reads the prologue.
cells in the vegetal half of the embryo should be unpigmented those in the animal half and there should be heavily pigmented.
Explanation:
The Yolk molecules moving in the vegetal halves of the egg which is the case in most of the animals, slows down the cell division. These lesser division area or the zone demarcates the area to be vegetal pole and due to lesser cell division, it becomes unpigmented or less pigmented Based on the observation time and perspect with assuming no movement.
The pole opposite to the vegetal, is animal pole which with absence or less of yolk, gets more ability to divide and hence become more pigmented or heavily pigmented. This brings polarity to the egg and becomes telolecithal egg.
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:
Both conditions are caused by an inability of the body to produce adequate acetylcholine.
Explanation:
Botulism is a potentially fatal condition caused by the toxin of bacteria <em>Clostridium botulinum</em>. Early symptoms are weakness, slurred speech, blurred vision etc. It may lead to vomiting, abdominal swelling and respiratory failure if not treated. The toxin hinders the release of neurotransmitter acetylcholine due to which motor neurons are not able to send signals to muscle cells. Muscles are not able to function properly due to which paralysis occurs.
Myasthenia gravis is also a neuromuscular condition like botulism. But unlike botulism release of acetylcholine is not hindered here. The receptors for acetylcholine are destroyed or altered by body's own immune system. Acetylcholine despite being present is not able to relay the signal which leads to muscle weakness. Symptoms are almost similar to those of botulism.
