Which two organs render an animal trefe under the category of chasairah (lacking the proper number)?
The two organs that render an animal trefe if lacking the proper number are the lungs and the feet (specifically the hindlegs).
Question 2
An animal's lung shriveled because it witnessed another animal being slaughtered nearby. What is the ruling?
Halachot 9–10 distinguish between fright caused by heaven (permitted after the water test) and fright caused by human action (forbidden outright).
Question 3
In an animal, the two thin sinews at the juncture are severed but the one thick sinew remains intact. What is the ruling?
The thick sinew is considered larger than both thin ones combined. Since the larger portion remains intact, the animal is permitted.
Question 4
For the liver to keep an animal kosher when mostly removed, what must remain?
An olive-sized portion must remain at the place from which the liver is suspended.
Question 5
An animal is born with only one kidney. What is its status for eating?
Removal of the kidneys — or being born with only one — does not render the animal trefe. However, a kidney that is extremely undersized does disqualify.