The mass of an atom is given by the sum of the number of PROTONS and the number of NEUTRONS since ELETRON'S mass is negligible.
The mass is 24+28 = 52.
Answer:
A
Explanation:
<em>lithosphere</em><em> </em><em>(land)</em>
<em>hydrosphere (water)</em>
<em>biosphere</em><em> </em><em>(living things)</em>
<em>atmosphere (air).</em>
