![](https://webarchive.library.unt.edu/eot2008/20081031172558im_/http://www.cancer.gov/images/spacer.gif) |
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![](https://webarchive.library.unt.edu/eot2008/20081031172558im_/http://www.cancer.gov/images/spacer.gif)
![](https://webarchive.library.unt.edu/eot2008/20081031172558im_/http://www.cancer.gov/images/spacer.gif)
| Total de todos los cambios químicos que tienen lugar en una célula o un organismo. Estos cambios producen energía y los materiales necesarios para el crecimiento, la reproducción y el mantenimiento de la salud. También ayudan a eliminar las sustancias tóxicas. |
![](https://webarchive.library.unt.edu/eot2008/20081031172558im_/http://www.cancer.gov/images/spacer.gif)
![](https://webarchive.library.unt.edu/eot2008/20081031172558im_/http://www.cancer.gov/images/gray_spacer.gif)
![](https://webarchive.library.unt.edu/eot2008/20081031172558im_/http://www.cancer.gov/images/spacer.gif)
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![](https://webarchive.library.unt.edu/eot2008/20081031172558im_/http://www.cancer.gov/images/spacer.gif) |