The decay of uranium isotopes is used to provide information about the age of Earth.
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Explanation:</h3>
Isotopes of Uranium U-232, U-233 , U-234 , U-235 , U-236 , U-238 are used as fuel in nuclear reactors or as explosives for nuclear weapons. Uranium 238 is not very radioactive and it constitutes for nearly 99.3% of natural uranium on Earth and has the longest lifetime: its period is 4.5 billion years, about the age of Earth.
Use of radiometric dating techniques help in defining the age of substances (natural or man-made) using the known decay rates of radioactive elements. Each element has an individual decay rate and half life time.
Two Uranium isotopes (U-238 and U-235) are used for radiometric dating. Both the isotopes have different decay rates and half life period. Both are unstable and radioactive. Since two different isotopes produce two different decay clocks (one as a reference to other), it is beneficial in accurately determining the age of samples. The age of earth (rocks or other natural elements) can be easily determined using Uranium isotopes.
Answer:
c. cysteine
Explanation:
Cysteine is a non essential amino acid. It contains sulfur in form of thiol group. A disulfide bond or bridge is formed between two thiol groups. It is represented as S-S. It is formed by oxidation of two cysteine molecules. The resultant disulfide bond is called as cystine which connects two polypeptide chains.
Cysteine is the only amino acid capable of forming disulfide bridge. It stabilizes protein's globular structure and plays an important role in protein folding and stability. Cysteine is required for protein synthesis, metabolic processes and detoxification. It is the part of beta-keratin which is the main protein in nails, hair and skin. If cysteine is mutated, formation of disulfide bond will be affected.
<span>Fungi obtain nutrients by absorption</span>
Answer:
b. axons
Explanation:
The Peripheral Nervous System consists of nerves and ganglia. Nerves are nothing more than bundles of parallelly arranged nerve fibers surrounded by connective tissue. Each of these fibers is formed by an axon and the sheaths surrounding it. The ganglia, in turn, are accumulations of neurons, which usually form spherical structures, are located outside the central nervous system and are also linked by axons bridges.
