NOT A TEACHER
1. "Edge" here means an advantage. Marketers are going to take advantage of the lefty marketplace.
Source: Longman Dictionary of Contemporary English8 I, for one, ... used to emphasize that you believe something, will do something etc and hope others will do the same : I, for one, am proud of the team’s effort.
3. I don't really understand the question... However, the author is trying to say, that he is all in favour of a society that encourages handedness of all types.
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