4.

A precursor is usually related to what precedes it. Evolve describes a development that is taking time to reach its final stage. So that means: “If monkeys are our precursor, then we are nothing but evolved monkeys!”

Discourse refers to an exchange of ideas. Interjections means to interject or to interrupt — they break into the conversation. So: “Gregorian was in discourse with his brother about the secret of the hidden treasure of Al Funcoot, but was repeatedly interjected by his brother!”

Conglomeration is a fancy word for a bunch of people brought together. If you lack a definite plan or purpose and flit from one thing to another, your actions are desultory. You know the drill: “The 2256 Conglomeration was not only desultory but boring as well!”