Suxamethonium is a

Correct Answer: A

Rationale: Suxamethonium (succinylcholine) is a muscle relaxant used in anesthesia. 'Depolarizing muscle relaxant,' is correct because it mimics acetylcholine, causing persistent depolarization and paralysis, per pharmacology texts (e.g., Katzung). 'Non depolarizing muscle relaxant,' (e.g., rocuronium) competes with acetylcholine, not depolarizes. 'Induction agent,' (e.g., propofol) induces unconsciousness, not relaxation. 'Reversal agent,' (e.g., neostigmine) counters non-depolarizing agents, not suxamethonium. Its depolarizing mechanism, ideal for rapid intubation, makes A the accurate answer.

Correct Answer: A

Rationale: The research process encompasses all stages of a study. 'Steps followed in carrying out a research,' is correct, covering problem identification to analysis, per research frameworks (e.g., Creswell). 'Analysis and presentation...,' is one phase. 'Identification and description...,' is the start only. 'Research design,' is a component. The holistic scope of A captures the full process, making it the precise answer.

Correct Answer: A

Rationale: Stroke volume (SV) is the blood pumped per beat, influenced by preload (ventricular filling). 'Preload,' is correct, per Frank-Starling law (e.g., Costanzo's Physiology). 'Postload,' is a misnomer; afterload resists SV. 'Cardiac output,' is SV × HR, not a determinant. 'Cardiac overload,' is vague. Preload's direct effect on SV makes A the accurate answer.

Correct Answer: C

Rationale: Progesterone, vital for maintaining pregnancy, is primarily secreted by the placenta after early ovarian production. 'Placenta,' is correct, per physiology texts like Guyton, sustaining uterine growth and preventing contractions. 'Anterior pituitary,' secretes FSH and LH, not progesterone directly. 'Ovary,' produces it initially via the corpus luteum, but the placenta takes over. 'Posterior pituitary,' releases oxytocin, not progesterone. The placenta's role post-first trimester, maintaining pregnancy through progesterone, distinguishes C as the accurate answer.

Correct Answer: B

Rationale: Human gestation averages 280 days (40 weeks) from the last menstrual period (LMP). '280 days,' is correct, per obstetrics texts like Williams Obstetrics, a standard clinical estimate. '250 days,' is about 36 weeks, preterm. '300 days,' (43 weeks) and '320 days,' (46 weeks) exceed typical full-term. The 280-day norm, aligning with fetal development, makes B the precise answer, widely accepted in medical practice.