Identify two structural features of purines and pyrimidines. purines contain four ring nitrogen atoms. contain only two ring nitrogen atoms. contain two heterocyclic rings. contain only three ring nitrogen atoms. contain one heterocyclic ring. pyrimidines contain only two ring nitrogen atoms. contain two heterocyclic rings. contain four ring nitrogen atoms. contain one heterocyclic ring. contain only three ring nitrogen atoms. classify each molecule as a purine or a pyrimidine. purines pyrimidines answer bank

iron and sleel

make siroeel

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.

i don,t know so just answer mine

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.