Choose the response that best fits the scenario. Which does not refer to physical appearance? aburrido feo gordo bonito.

By what percent will the product of two numbers change, if the first number increases by 70%, while the second number decreases by 40%.

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

The authors use the word “backbone” in lines 3 and 39 to indicate that