Imam Mohammad Baqir(as) gave some very informative answers to some of the most difficult questions to his disciples and others. Some of them are reproduced here:
Question: Which was the Roza (fast) in which eating and drinking was permitted?
Answer: The Roza (fast) that Hazrat Mariam(as) observed in which she abandoned talking only.
Question: What decreases and never increases with time?
Answer: Age [Time left for us in this world]
Question: What increases and never decreases?
Answer: Water of the ocean.
Question: What was raised in the sky only once?
Answer: The mountain of Toor which was raised above Bani-Israel only once and then put down.
Question: Who are the people whose true testimony was declared a lie?
Answer: These are the munafiqeen (hypocrites) whose testimony that “Prophet is the messenger of God” was not accepted and they were declared liars by Allah(s w t).
Question: When was one third of the mankind killed?
Answer: Never – however one fourth of mankind was killed when Qabeel murdered Habeel. At that time, whole of mankind consisted of 4 persons only.
Question: You Muslims believe that the food and drinks of Jannah will not cause necessity to urinate and pass stool. Is there any example of this in this world?
Answer: Yes there is. The child inside the womb of the mother gets fed without the necessity to urinate or pass stool.
Question: Who are the two people who were born at the same time and died at the same time but one was 50 years and the other was 150 years old at the time of death?
Answer: These were brothers Uzair and Aziz. Allah(s w t) gave temporary death to Uzair for 100 years. When he brought back to life, he died again at the same time as did Aziz, so the difference in their ages was 100 years.