When faced with a licensing exam, don't struggle with test anxiety! Use the question below and others from our Exam Study Guide series to study and prepare for exam questions. Take a look at this sample water treatment licensing question along with an explanation of the correct answer.Sample question:What is the percent oxygen of normal air at sea level?A) 20.9 percent
B) 19.5 percent
C) 15 percent
D) 18.5 percentAnswer: Normal air is mostly nitrogen and oxygen with a few traces of other inert gases. At sea level, normal air is about 78.1 percent nitrogen and 20.9 percent oxygen. When working in a confined space, it is important to continually
