Two technicians are discussing valve body checks. Technician A says a test for a sticky valve is to make sure that the all valves will free fall out of its bore. Technician B says that an aluminum valve can be checked by seeing how much side clearance it has by trying to wiggle it in its bore. Which technician is correct?a. Tech A
b. Tech B
c. Both A and B
d. Neither A nor B

the answer for apex is the lowest

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me