Help me please... tyy if you do :))

a) HCl

Explanation:

As we know, that HCl or Hydrogen Chloride is a diatomic compound. It is formed due to the Chemical reaction of Hydrogen and Chlorine. As both Hydrogen and Chlorine have valencies of 1, the Net Valency of the Compound HCl is 1 itself. This separates it from the rest of the compounds. The rest of the compounds need to have more than 2 atoms of each kind and have different valencies too.

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.