How many moles are in 6.21x1025 atoms of magnesium oxide?

55.56 moles of MgO

Explanation:

1 mole = avogadro number

if 6.21x10^25 atoms then molecules of MgO (equal numbers of Mg and O atoms)

= 0.5*6.21x10^25 = 3.105 molecules of MgO

So moles of MgO = 0.5*6.21*10^25/avogadro number = 55.56

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.