What is netzal and what is its minimum measure for impurity?
Halacha 1: Netzal is flesh that has decomposed into a putrid liquid. It imparts impurity when an olive-sized portion is present, provided the liquid coagulates (proving it is from the flesh, not phlegm).
Question 2
How many bones constitute 'majority of number' to render a collection equal to a full corpse?
Halacha 8: The majority of a man's 248 limbs is 125 bones. If there are 125 or more, they are like a full corpse; 124 or fewer, they are like ordinary bones.
Question 3
Does a quarter-kab of bones from TWO different corpses impart ohel impurity?
Halacha 1 of chapter 4 (the opening): A revi'it of blood, a backbone, skull, quarter-kab of bones, and a limb — all require coming from ONE corpse to convey ohel impurity. If from two corpses, only touch and carrying impurity applies.
Question 4
What is rekev and what are its impurity properties?
Halacha 12: Rekev is bones that have decomposed in the grave. Two handfuls of rekev impart carrying and ohel impurity but NOT touch — because it cannot be touched as a whole entity.
Question 5
What are the impurity properties of the golel (grave covering)?
Halacha 16: The golel and dofek impart touch and ohel impurity (like a grave) but NOT carrying impurity, and their impurity is Rabbinic, not Torah law.