Question

identifying causes and effects
a model entrepreneur is art fry, a chemical engineer who in 1974 was working in product development at 3m during the week and singing in his church choir on sundays. he was accustomed to marking the pages in his hymnal with scraps of paper, so that he could quickly locate the songs during the two services at which he sang. the procedure worked fine for the first service, but often by the second one some of the loose scraps of paper had fallen out of their places. fry, not having noticed this, was sometimes at a loss for words.
—the evolution of useful things, henry petroski
what made fry start thinking about an invention?
○ singing in his church choir
○ the failure of bookmarks
○ an article in the sunday paper
○ the success he had locating songs

Explanation:

The text describes Art Fry's experience. He used scraps of paper as bookmarks in his hymnal. These scraps often fell out during the second service. This failure of the makeshift bookmarks (the scraps of paper) led him to start thinking about an invention. The other options - singing in the church choir (he already did that and it was the bookmark failure that was the trigger), an article in the Sunday paper (not mentioned in the text), and the success of locating songs (the opposite, as the bookmarks failed) - are not the cause.

Answer:

the failure of bookmarks