In order to determine the lattice formation energy for KCl, the following data are provided: Ionization energy of K(g) = 425 kJ/mol
Electron affinity of Cl(g) = –349 kJ/mol
Energy to sublime K(s) = 89 kJ/mol
Bond energy of Cl2(g) = 240 kJ/mol
ΔHf for K(s) + ½Cl2(g) → KCl(s) = –438 kJ/mol

Sort the steps of the Born–Haber cycle according to the sign of the energy change associated with each.

K(g) → K^(g)+ e
K^+(g) + Cl^- →KCl(s)
K(s) + K(g)

the answer would be a

the answer is c. nacl

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.