+Ca2+, the calcium ion, is a divalently charged cation, fundamental to all life. It plays critical roles in [Cell Signaling](/wiki/cell_signaling), muscle contraction, and maintaining bone structure. Its precise regulation is vital for [Biological Processes](/wiki/biological_processes) across organisms.
+## See also
+- [Calcium](/wiki/calcium)
+- [Ion Channels](/wiki/ion_channels)
+- [Bone](/wiki/bone)
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