Correct Answer: D

Rationale: Tachycardia is an increased heart rate, and it can be caused by various factors such as fever, exercise, and sympathetic nervous system stimulation, all of which tend to increase heart rate. However, parasympathetic nervous system stimulation typically slows the heart rate, making it the exception among the choices provided. Thus, parasympathetic nervous system stimulation is not a cause of tachycardia.

Correct Answer: A

Rationale: The nurse's responsibility in this scenario is to instruct the patient about the diagnostic test ordered by the physician. This includes explaining the purpose of the test, any necessary preparations, and what to expect. The nurse is not responsible for writing the order, as this is the physician's role. Additionally, providing breakfast is not directly related to the platelet count test. Therefore, the correct answer is A, which aligns with the nurse's role in educating and supporting the patient regarding the test.

Correct Answer: D

Rationale: As individuals age, various changes occur in the vascular system. These changes include increased peripheral resistance of the blood vessels, decreased blood flow, and an increased workload of the left ventricle. Therefore, all the listed changes result from aging, making option D, 'All of the above,' the correct answer.

Correct Answer: C

Rationale: The absence of the pedal pulse may not be significant if the patient has poor peripheral circulation or if the healthcare provider is focused on other pulse points. The pedal pulse is often weaker and may not always be palpable due to various factors, making its absence less concerning in certain situations. However, the absence of other pulses like radial or femoral pulses may indicate more critical conditions and require immediate attention.

Correct Answer: D

Rationale: In Maslow's hierarchy of physiological needs, the most basic and immediate need is physiological survival, which includes the need for oxygen. Without oxygen, the body cannot survive for more than a few minutes, making it the highest priority physiological need according to Maslow's hierarchy.