Which prefix means 'against' as in antitoxin?

Which prefix means 'against' as in antitoxin?

• A. An-
• B. Contra-
• C. Auto-
• D. Anti-

Answer: (D)

Think about how prefixes show opposition. The prefix anti- means against or opposing. When you put anti- in front of toxin, you get antitoxin, which is something that neutralizes or counters the toxin’s effects. That exact sense of opposing the toxin is what the term conveys, making anti- the best fit. The other prefixes don’t express that opposing relationship in this medical term: auto- means self, an- isn’t used here to indicate opposition, and contra- also means against but isn’t the form used to create this specific word.

Think about how prefixes show opposition. The prefix anti- means against or opposing. When you put anti- in front of toxin, you get antitoxin, which is something that neutralizes or counters the toxin’s effects. That exact sense of opposing the toxin is what the term conveys, making anti- the best fit. The other prefixes don’t express that opposing relationship in this medical term: auto- means self, an- isn’t used here to indicate opposition, and contra- also means against but isn’t the form used to create this specific word.