ALEXANDRIA, Va. (AP) — Google opened its defense against allegations that it holds an illegal monopoly on online advertising technology Friday with witness testimony saying the industry is vastly more complex and competitive than portrayed by the federal government. “The industry has been exceptionally fluid over the last 18 years,” said Scott Sheffer, a vice president for global partnerships at Google, the company's first witness at its antitrust trial in federal court in Alexandria. The Justice Department and a coalition of states contend that Google built and maintained an illegal monopoly over the technology that facilitates the buying and selling of online ads seen by consumers.