[C] aging may not be caused by the body’s genetic program
[D] normal development dictates the maximum age of a person
27. The example of the “aging car” is used to make the point that .
[A] aging is actually a by-product of the life process
[B] any car may break down or collapse over time
[C] no car can function at optimum levels due to inferior fuel
[D] efficient rate of combustion is most important to the car
28. A “basic trade-off” (Line 3, Para. 3) is a process .
[A] by which old cars are traded off for new ones
[B] by which any organism depends on others for oxygen
[C] through which an organism gets rid of harmful substances
[D] in which any use carries with it an inherent side effect
29. Which of the following statements is true according to the passage?
[A] Aging would never take place if we developed a special fuel additive.
[B] We would live forever if we developed a magic medicine for longevity.