The arrival of new diseases and strains of bacteria that are resistant to older drug treatments makes which step of the engineering process essential?

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock

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.