Answer:
Calcium
Explanation:
Calcium is an essential part in the strength of bones & teeth's, for it is a key component in the creation of the structures as well as the outer hardness of the two.
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Earth can be considered as a closed system, since it only receives sunlight (energy), while the overall mass stays constant, without (almost) any exchange from space. Another example of a closed system is a saucepan or frying pan, on a stove, when its lid is closed.
Because they provide a predictable income
Answer:
Ulysses, Kansas is in the South West portion of Kansas
(If you need further discription, let me know).