<span>division of Earth's history into time units based largely on the types of life-forms that lived only during certain periods.</span>
Answer:
your question in not complete.
you need to the high too.
Hello,
The question states: <span>The Robinson projection map is considered very useful because...
The answer is

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~FoodJunky
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Answer:
15
Explanation:
The mass number is defined as the total number of protons and neutrons. The atomic number is total number of protons. And since we have the mass number and number of neutrons, we can use simple subtraction (30 - 15) to find that the atomic number is 15.