A scientific theory generally is accepted as what until it is what? is it true or false and is it proved or disproved

Two technicians are discussing how to test a car's exhaust by holding a small piece of paper within an inch of the tailpipe mouth. technician a says that if the paper is vibrating due to a "puffing" output from the tailpipe, this signals a smoothly running engine. technician b says that if the paper is being drawn toward the tailpipe, this could indicate burned exhaust valves. who is correct? a. technician b b. both technicians a and b c. technician a d. neither technicians a or b

Given: m∠apc = 27°, m dc = 27° find: m ab

Tissues that carry food water and nutrients throughout the plant