Planets reflect sunlight. Most planets are close enough to the sun that they can reflect its light and that is why you can see them. Some planets that are far from the sun do not light up because they have no light to reflect.
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Molarity
Molarity is a unit used to express the concentration of a substance, and it is defined as the number of moles of solute per decimeter cubed (liter) of solvent.
Answer:
Beryllium, because it is in period 2 and has four total electrons.
Explanation: