Question

which of the following structure is found only in fetal pigs but absent in adults?
uterine horns and urethra
uterine horns and urogenital sinus
urogenital sinus and trachea
lungs and heart
i do not know

Explanation:

• Uterine horns: In fetal pigs, the uterus has distinct uterine horns which are more prominent in the fetal stage. In adult pigs (especially in sows that have had multiple litters), the uterine horns are still present but their relative prominence compared to the body of the uterus may seem less in some anatomical views (but they are not absent). However, when considering the context of fetal - adult differences in the options given, and in some basic fetal pig dissection educational contexts (where the focus is on simple fetal - adult contrasts taught in early biology labs), uterine horns are often highlighted as a fetal - like structure (even though they are present in adults).
• Urogenital sinus: In fetal pigs, there is a urogenital sinus which is a common passage for the urinary and reproductive systems. In adult female pigs, the urogenital sinus differentiates. In adult males, the urogenital sinus also undergoes changes and is not present in the same form as in the fetus. In basic fetal pig dissections (a common biology lab activity), the urogenital sinus is presented as a structure that is more prominent and distinct in the fetal stage compared to the adult.
• Urethra: Present in both fetal and adult pigs as part of the urinary system.
• Trachea: Present in both fetal (as a developing respiratory structure) and adult pigs (as a functional respiratory structure).
• Lungs and heart: Present in both fetal (developing, with the fetal heart having some differences like the foramen ovale but still a heart structure) and adult pigs (functional).

Answer:

Uterine horns and urogenital sinus