Question 1
The prefix contra- means "against," as in contradict. In common English, the related form counter- carries the same meaning, as in counteract. What do contra- and counter- mean?
Both "contra-" and "counter-" mean "against." "contra-" appears in Latin-origin words: in contradict, it means to speak against. "counter-" appears in common English: in counteract, it means to act against.