for the reaction 2Na+2H2O->2NaOH+H2 how many grams of sodiun hydroxide, NaOH are produced from 2.0 mole of water

catya your not at all which answer i've seen you do this on another question!

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.