Describe how the U.S. Constitution applies to real estate transactions. How does it relate to other ...

The U.S. Constitution is pervasive in real estate transactions in everything from eminent domain to fair housing laws. The U.S. Constitution provides protections against discrimination and guarantees due process in eminent domain and foreclosure proceedings.
The U.S. Constitution is controlling. Other laws cannot violate the rights given in there. Nor can other laws infringe on the powers exercised by Congress. For example, Congress can regulate interstate real estate activity. States regulate local activity such as licensing.