Answer to Question 1
A
Genetic researchers have found that telomeres shorten with each cellular reproduction and con-tinue to do so until the cell dies. Selected animal studies since the 1930s conclude that calorie restrictions of 30 can lead to a longer life expectancy, slower metabolism, lower body temper-ature, and delay of age-related disorders. The pacemaker theory, which is also known as the neuroendocrine control theory, holds that critical functions of selected endocrine glands slow and can halt with age. The cross-link theory suggests that aging is a result of the stiffening of proteins caused by cross-linking, leading to stiffer joints, rougher skin, and decreased cellular elasticity.
Answer to Question 2
D
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A Incorrect. Weber's test with the tuning fork is used to detect conductive hearing loss.
B Incorrect. Presbycusis affects both ears and is of sensorineural origin. The tuning fork test is used to detect conductive hearing loss in one ear.
C Incorrect. Tinnitus is a hearing sensation not caused by an actual sound. The tuning fork test is used to detect hearing loss caused by poor sound conduction.
D Correct. Weber's test, in which a vibrating tuning fork is placed on the center of the forehead, detects differences in hearing between one ear and the other caused by poor sound conduction. During testing, the patient is asked to de-scribe the sensation felt when the tuning fork is activated and then placed on the forehead. If hearing by conduction is intact, the patient will feel vibrations con-ducted through bones of the skull from the tuning fork.