Phrases can sometimes be paraphrased into clauses. For example, the importance of something can be paraphrased as how important something is.
It seems that the clause version is used mainly as the object position. Can it be used as the subject position? For example, in (1) which sentence is better? Is either ok? Which is more appropriate in (2)?
a. The degree of dependence on nuclear energy varies from country to country.
b. How dependent on nuclear energy varies from country to country.
a. How to read books varies from person to person.
b. The way of reading books varies from person to person.