A fracture united in unacceptable alignment is termed as:

Correct Answer: C

Rationale: The correct answer is C: Malunion. Malunion refers to a fracture that has healed in an unacceptable alignment. This occurs when the fractured bones do not align properly during the healing process, leading to deformity or functional impairment. Delayed union (A) is when a fracture takes longer than usual to heal. Crepitus (B) is a term used to describe a grating or crackling sound or sensation in a joint. Nonunion (D) is when a fracture fails to heal altogether. Malunion specifically addresses the issue of improper alignment post-fracture healing, making it the most appropriate choice in this scenario.

Correct Answer: C

Rationale: The correct answer is C: Iris stroma. The iris stroma contains melanocytes, which are responsible for producing the pigmented cells that determine eye color. These pigmented cells give the iris its color by absorbing and reflecting light. The ciliary epithelium (choice A) is not involved in determining eye color. The iris epithelium (choice B) is mainly responsible for controlling the size of the pupil, not for determining eye color. The corneal stroma (choice D) is a layer of the cornea that primarily provides structural support and transparency to the eye, but it does not play a role in determining eye color.

Correct Answer: D

Rationale: The correct answer is D: zygote. After fertilization, the sperm and egg unite to form a zygote, which is the initial cell of a new organism with a full set of chromosomes. A gamete (A) is a reproductive cell before fertilization, an embryo (B) is the early stage of development after the zygote, and a fetus (C) is the later stage of development in the womb. Therefore, the zygote is the correct term for the cell produced by fertilization.

Correct Answer: D

Rationale: The correct answer is D: Pulmonary vascular resistance decreases. After birth, the lungs expand and start functioning, leading to increased oxygen levels, which causes the pulmonary vascular resistance to decrease. This allows blood flow to the lungs and decreases pressure in the pulmonary artery. A: Systemic arterial pressure increasing does not directly affect the pressure in the pulmonary artery. B: Ductus arteriosus closing is part of the normal postnatal changes but does not directly cause the decrease in pulmonary artery pressure. C: Left ventricular pressure increasing is a consequence of the closure of the ductus arteriosus but does not explain the decrease in pulmonary artery pressure.

Correct Answer: B

Rationale: The correct answer is B because blocking the smooth muscle receptors for nitric oxide would interfere with vasodilation necessary for an erection during the emission phase of the sexual act. Choice A would actually enhance the effects of nitric oxide, Choice C would increase nitric oxide release which would typically improve sexual function, and Choice D, a testosterone-like androgen compound, would not directly affect the emission phase related to nitric oxide.