A sulfur atom has 16 protons and 16 electrons. If you add a proton to a sulfur atom, what have you done? Created an isotope of sulfur. Created a positively charged ion of sulfur. Created a negatively charged ion of sulfur. Converted the atom into a different element.

Created a positively charged ion of Sulfur

Explanation:

As the number of protons in Sulfur is more than the electrons in Sulfur, thus it'll be a positively charged ion of Sulfur

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.