Verb semantics – choose the action verb that fits the imperative of stopping pollution: complete the sentence with the most semantically appropriate verb. Sentence: "Man must ____ to stop pollution." Select the verb that expresses taking action.

Given data

• Context: urging humans to take measures against pollution.
• We need a succinct verb meaning "take action".

Concept/Approach
Act means to take action or do something. Perform requires an object (perform a task). Operate usually refers to machinery or functioning of systems. Behave is about conduct, not necessarily intervention.

Option analysis
act — concise and idiomatic in calls to action: "We must act to…" ✅perform — incomplete without a noun phrase; semantically off.operate — refers to running machines or functioning.behave — about manners/ethics; doesn't capture initiative.

Final Answer
act