Answer:
C
Explanation:
u can't touch a chemical with bare skin
Its has 24 protons, 24 electrons, and 28 nuetrons
1) START counting for sig. figs. On the FIRST non-zero digit.
2) STOP counting for sig. figs. On the LAST non-zero digit.
3) Non-zero digits are ALWAYS significant.
4) Zeroes in between two non-zero digits are significant. All other zeroes are insignificant.
B) oxygen, because oxygen is the only element that is in both chemical formulas.