Fry remembered a curious adhesive – a strong and yet easily removed “unglue”– that Spencer Silver, another 3M researcher, had come upon several years earlier. . . . Silver felt the unusual adhesive might have some commercial value, and so he demonstrated it to various colleagues, including Fry. At the time, no one had come up with a use for it, and so the formula for the weak adhesive was filed away – until the Monday morning when Fry came to work with the idea of making sticky bookmarks that could also be removed without damaging the book.

Question

—The Evolution of Useful Things,
Henry Petroski

Why was Spencer Silver's work an essential part of Fry's invention?

He worked alongside Fry on the sticky notes.
He convinced other people to believe in Fry's invention.
He told Fry about the "unglue" that he had discovered.
He came up with a commercial use for the "unglue."

Answer 1

The correct answer is: He told Fry about the "unglue" that he had discovered.

Spencer Silver's work was essential to Fry's invention because it was Silver's discovery of the unique adhesive that inspired Fry to think of a practical application for it – the creation of sticky bookmarks that could be easily removed without damaging the pages of a book. Without Silver's initial discovery, Fry would not have had the idea for the sticky notes.