B) oxygen, because oxygen is the only element that is in both chemical formulas.
It may just be my internet but the picture is just white. maybe try reposting this..?
Science, Economics, Statistics, Finance, and many other areas of life where we are measuring things to a certain level of accuracy.
Answer: A Ruler
Explanation:A Ruler is a common instrument used for measuring the length of small objects. It usually has four units of measurement to choose from: millimeter, centimeter, inch, and foot.
Keep in mind that atomic number is the number of protons in the atom of the element. Therefore, in the case where there are 78 protons, we can conclude that the atomic number of this element is ALSO 78.
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- Dotz
