Personnel in wheeled vehicles should take what action before vehicle wash down?

Turn off the engine of the car and close the car windows.

Explanation:

Before going into the car wash, personnel still sitting in the car must turn off the engine of the car so that nothing unfortunate may occur. The most important action that must be taken is the closing of windows.

If the windows are kept open, the person sitting will also get a wash alongside. All the soap and water will rush into the car and it can very quickly turn into a miserable experience.

increased stability in the completion of fluorine's outer shell.

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.