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.
 
        
             
        
        
        
A multicellular organism develops from a single cell.
        
             
        
        
        
Answer: Testosterone, follicle stimulating hormone
Explanation:
Testosterone is a sex hormone produce by the male sex organs or testes typically in the seminiferous tubules. It incudes male sexual characteristics that is the production and development of sperms in males. The follicle stimulating hormone is involved in causing the maturation of the eggs or female gametes in the female sex organs or ovaries. It also induces the mensuration cycle in females. FSH also have a role in stimulating the spermatogenesis in males as it acts on the Sertoli cells of the testes and stimulates the sperm production. 
 
        
             
        
        
        
Answer:
When two or more atoms link up, they create a molecule . A molecule of water is made of two atoms of hydrogen (H) and one atom of oxygen (O). The molecular mass is the sum of the masses of all the atoms in the molecule. A collection of molecules is called a compound.
Explanation:
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