Facebook was built on the _____ of earlier social network sites like Myspace and Bebo.
Correct Answer: EASY
A. succeed (v) succeed
B. successful (adj) successful
C. successfully (adv) successfully
D. success (n) success
The position to be filled is a noun because preceded by the article the
=> Facebook was built on the success of earlier social network sites like MySpace and Bebo.
=> Facebook built on the success of previous social networking sites like MySpace and Bebo.
The answer to choose is: EASY