Can an olive of flesh from corpse A and an olive of netzal from corpse B combine for impurity?
Halacha 3: Flesh and netzal are equivalent in their measure (kzayit) and therefore combine across two corpses. Half-olive of each adds up to a full olive, conveying impurity.
Question 2
An olive of flesh from a corpse is cut into pieces, reassembled, and carried under one ohel. Does it convey impurity?
Halacha 5: When an olive of flesh is cut and rejoined, it imparts ohel and carrying impurity (as a whole) but does not impart touch impurity to individual pieces, because human joining is not valid joining.
Question 3
What happens to a revi'it of blood once it is absorbed into the ground?
Halacha 11: Once a revi'it of blood is absorbed into the earth, the house is pure going forward. Only whatever was in the house at the moment of absorption is retroactively impure.
Question 4
When two handfuls of rekev (decomposed matter) are scattered throughout a house, what is the ruling?
Halacha 10: Two handfuls of rekev scattered in a house renders the house impure — the ohel joins together what is scattered within it.
Question 5
A piece of bone with an olive of flesh that grew on it naturally is partially inserted into a house. Is the house impure?
Halacha 9: Flesh grown on a bone 'by heaven' (naturally) is valid joining. Inserting even part of such a bone-with-flesh into a house makes the house impure.