4.
What is a substrate control? Why is it done?

a substrate control is an uncontaminated sample

Explanation:

it allows forensic scientiststo compare the two samples to better observe whether a flammable liquid is present

vehicle inspection tests are conducted to ensure that a vehicle is safe to operate. during the vehicle inspection test, you will be expected to explain or show your knowledge of the vehicle inspection process.

during the vehicle inspection test, you must show that the vehicle is safe to drive. you will have to walk around the vehicle and point to or touch each item and explain to the examiner what you are checking and why. you will not have to crawl under the hood or under the vehicle. the brake lights, emergency flashers, turn signals, and horn must be checked. if any of these items do not work, the skills and road portions of the test will be postponed.