Question

books that were deteriorating, but the more recent volumes: those produced since the middle of the nineteenth century with sheets fabricated from a highly acidic wood - pulp mixture. (3) the transition to this lesser - grade stock began during the 1860s, when increasing demand for paper hastened the development of a cheaper process. (4) to improve strength and to prevent ink from being too readily absorbed by the pulp paper, chemicals, including aluminum sulfate (alum), were added to the mix. (5) the result was that documents exposed to humidity produced sulfuric acid, which weakened the molecular structure of the pulps cellulose. which of the following best describes the organization of the passage as a whole? a problem is presented and two solutions are evaluated. an approach is presented and found to be unreliable. a theory is proposed and challenged with new evidence. a phenomenon is described and an explanation is provided. a procedure is introduced and then described in more detail.

Explanation:

The passage first describes the phenomenon of books deteriorating (those from the mid - 19th century onwards with acidic wood - pulp sheets). Then it provides an explanation about the transition to the lesser - grade stock (due to increasing paper demand in the 1860s), the addition of chemicals (like aluminum sulfate) to improve strength and ink absorption, and how this led to document deterioration (sulfuric acid weakening cellulose).

Answer:

A phenomenon is described and an explanation is provided.