Why not just say, after discussing the intricacy, the beauty, the adaptability built into most life forms, the stunning complexity, something like "Is it possible that this was all random happenings, or perhaps Intelligently Designed?"

It's not necessary to go into any further detail at all. It gives both possible causes, without CLAIMING either to be truth.

Realistically, man has pondered many things through the ages, and it's right to do so. You can't teach everything, and you can't learn everything.... Many things need to be pondered, wondered about, speculated on....

Students should be given questions..... They shouldn't expect all the answers to be given to them. Thinking is mandatory, not optional.