Which of the following is true of informed consent?

Correct Answer: C

Rationale: Informed consent is a legal and ethical process ensuring patients understand and agree to treatment. 'Patient can revoke consent even if he has been booked for surgery,' is correct because consent is voluntary and revocable at any time, per healthcare law (e.g., Schloendorff v. Society of New York Hospital, 1914). 'It can be obtained from a minor,' is false; minors typically require guardian consent unless emancipated. 'It is the duty of the Nurse to obtain consent,' is incorrect; physicians usually secure it, though nurses witness. 'It can be implied for any invasive procedure,' is wrong; implied consent applies only in emergencies. The patient's right to withdraw consent reflects autonomy, making C the accurate answer, grounded in legal precedents.

Correct Answer: A

Rationale: Inhalation anesthesia systems vary by gas flow and rebreathing. 'Semiclosed system,' is correct as the most widely used, balancing efficiency and safety with partial rebreathing (e.g., circle system), per Miller's Anesthesia. 'Closed system,' fully recycles gases, less common due to complexity. 'Semiopen system,' is a misnomer; it's not standard. 'Open system,' (e.g., mask without rebreathing) is rare today. Semiclosed systems' prevalence in modern operating rooms, optimizing gas use and monitoring, makes A the precise answer.

Correct Answer: B

Rationale: A dependent variable is the outcome measured in research, affected by the independent variable. 'An effect variable,' is correct, aligning with experimental design (e.g., Campbell & Stanley), where it reflects changes (e.g., pain level post-treatment). 'Manipulated,' describes the independent variable. 'An intervention variable,' is also independent. 'An interdependent variable,' is not standard; variables may correlate, but dependent' means effected. B's focus on the variable being influenced matches its role, making it the precise answer.

Correct Answer: A

Rationale: Thoracic vertebrae (T1-T12) lack transverse foramina, present in cervical vertebrae for arteries. 'Transverse foramina,' is correct, per anatomy texts (e.g., Moore's Clinically Oriented Anatomy). 'Transverse processes,' articulate ribs. 'Pedicle,' and 'Spinous processes,' are standard features. The absence of transverse foramina in thoracic vertebrae makes A the accurate answer.

Correct Answer: B

Rationale: The SA node's pacemaker potential results from calcium influx via T-type channels, depolarizing cells. 'Calcium,' is correct, per cardiac physiology (e.g., Opie). 'Sodium,' contributes later in action potentials. 'Potassium,' hyperpolarizes. 'Magnesium,' is minor. Calcium's role in phase 4 depolarization makes B the precise answer.