|MadSci Network: General Biology|
Humans (and all animals) eat because they need nourishment. The nourishment provides calories (or energy) for things like moving around, thinking, and growing. In addition, food provides the stuff that we are made of like amino acids to make proteins, like those in the brain and muscle, calcium for bones and teeth, iron for blood, minerals, salt, vitamins, etc. I don't know exactly what your teacher was expecting, but I suspect that this is (s)he meant. I hope this helps. The following web site provide information about nutrition: http://navigator.tufts.edu/ http://www.nal.usda.gov/fnic/ http://www.nutrition.gov/
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