The element starts off as 100%. half of 100% is 50% and half of 50% is 25%. the element has emitted 2 times the half life which is 10,000 x 2 = 20,000
the fossil bone is 20,000 years old
        
             
        
        
        
Hello Yosamy, 
This is a rather broad question but I guess one way you can answer this is.
In the year of 1970 scientists began bio-genetic engineering.
~Naterator
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<span>Rough ER is called rough because it has ribosomes attached to its surface. The double membranes of smooth and rough ER form sacs called cisternae. Protein molecules are synthesized and collected in the cisternal space/lumen. When enough proteins have been synthesized, they collect and are pinched off in vesicles.</span>
        
             
        
        
        
(4) organic catalysts
The job of catalysts in chemical reactions is to make the reaction go faster by lowering the amount of energy needed to activate the reaction. If less energy is needed for the reaction to occur, then the reaction can go faster because a large energy build-up is not needed.