6. The three basic sources of vehicle emissions are engine crankcase __ fumes, fuel vapors and engine exhaust gases. (A) blowby (B) exhaust (C) intake (D) vaporized

## Step 1<br />The problem is asking us to identify the correct term that completes the sentence about the three basic sources of vehicle emissions. The sentence already mentions engine crankcase fumes, fuel vapors, and engine exhaust gases. <br /><br />## Step 2<br />We need to choose the term that best fits the context of the sentence. The term should be related to the emissions from a vehicle's engine.<br /><br />## Step 3<br />Looking at the options, we can see that 'blowby' is the term that fits best. 'Blowby' refers to the gases that escape from the engine's crankcase during operation. This is a common source of emissions in vehicles.