On the Quality Score allegations, Google said all the major search engines used such a system to make sure their users see the relevant adverts.
"These quality scores are determined based on our assessment of the relevance of the ad to the query and whether the site provides useful information," said the statement. "We also inform advertisers of their quality scores and give them tips on how to improve them."
"Typically, the sites that complain about quality scores have less relevant, lower quality content which we have learned our users are less interested in seeing."
The web goliath added it had stopped using exclusive contracts almost two years ago.
"Our contracts with computer and software vendors, where we provide search services, are all short term," it said. "And most importantly, these contracts can't prevent users from choosing other search providers."
However, despite its protests, Google has said it would work with the EC to "address any concerns."
No time scale has been put on the investigation as of yet.
"There is no legal deadline to complete inquiries into anticompetitive conduct," said the EC. "Their duration depends on a number of factors, including the complexity of each case and the extent to which the undertakings concerned co-operate with the Commission."
