Your answer is a , atoms .
The right answer is C. I think, a. and d. are obviously not serious. B is not true, because Ag and Au are in the same group in the periodic table and therefore have the same number of electrons in the last level. So, they form ions with the same charge. C is true beacause Ag and Au have different numbers in the periodic table and different amount of protons and neutrons in their nucleuses.
The federal government regulates and controls the economy through numerous laws affecting economic activity.
I hope that answers your question.
