This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infant deaths & child abuse, Subject name: Forensic Medicine
Wredin's test is to demonstrate: 
Select and explain. 
A. Live bih, B. Insanity, C. Putrefaction, D. Assault
A: Live bih
Answer: A: Live bih 
Explanation: TESTS FOR LIVE BORN VS DEAD BORN :- Hydrostatic test :- Specific gravity of lungs decreases after respiration and respired lungs will float in water. Fodere's test :- Weight of Lungs increases due to increase in blood flow after respiration. Plocquet's test:- Ratio of the lung wt. to body wt. almost doubled after respiration. Wredin's test :- presence of air in middle ear after respiration. Breslau's second life test/stomach bowl test :- presence of swallowed air in the stomach /intestine after respiration.