-Why is is it difficult for historians to study the Harrapan people of the Indus River Valley?

Historians did not learn much about the Harappan civilization from written sources because its writing system has not yet meen figured out. They learned much from building remains, like the drainage system, and where grains were stored.

Explanation:

there are a number of different ideologies that come into conflict with regard to immigrants and immigration to the us.