Research process is

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: 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.

Correct Answer: B

Rationale: The nephron is the kidney's structural and functional unit, filtering blood and forming urine. 'Nephron,' is correct, per physiology texts like Vander, encompassing glomerulus and tubules. 'Glomerulus,' is part of the nephron. 'Renal artery,' supplies blood. 'Bowman's capsule,' encases the glomerulus within the nephron. The nephron's comprehensive role in filtration, reabsorption, and excretion makes B the precise answer.

Correct Answer: D

Rationale: Accessory digestive organs aid digestion outside the alimentary canal. 'Kidney,' is correct as the exception, filtering blood, not digesting, per physiology (e.g., Guyton). 'Liver,' produces bile. 'Pancreas,' secretes enzymes. 'Gall bladder,' stores bile. Kidney's excretory role distinguishes D as the accurate answer.