What is the explanandum in this passage

Why does c. wright mills identify critical thinking as one of the most important criteria for the development of intellectual craftsmanship? why is constantly being aware of the biased nature of your reactions and interactions (what c. wright mills calls self-reflexive) key to the development of that critical thinking? finally, why is keeping a file important, how can it lean to intellectual curiosity which can foster critical thinking and to develop a keen analytical mind?

Refers to the biological heritage people use to identify themselves.

Why would someone who is studying the history or culture of this time. find this text interesting important or useful?