What key concepts of the Church allowed for indulgences to take off?

Indulgence, a distinctive feature of the penitential system of both the Western medieval and the Roman Catholic Church that granted full or partial remission of the punishment of sin.

Explanation:

b.

jim crow laws were enacted in northern states.

the answer is a. the harappan civilisation is also called the indus valley civilisation, this is because they built their cities along the indus river. the reason behind this location can be found in the rest of the "old world" civilisations like mesopotamia or egypt, the first built their cities along the rivers tigris and euphrates, the second along the nil; : their respective civilisations thrived because the overflowing of their respective rivers produced favorable conditions for agriculture, their main support.