Meaning: 'Combat' means to fight against or take action to reduce something harmful, in this case, pollution from cigarette butts.

Wrong options:

• commit: 'Commit' means to pledge or dedicate oneself to a cause, but it does not convey the action of fighting against a problem, making it contextually inappropriate here.
• commune: 'Commune' refers to sharing or communicating, which does not fit the context of taking action against pollution.
• comply: 'Comply' means to act in accordance with a rule or request, which does not convey the active fighting against pollution that 'combat' does.

Correct answer: discarded

Explanation: The word 'discarded' is the correct choice as it refers to something that has been thrown away, which is the context of cigarette butts left in public places. It fits grammatically and contextually, as it describes the state of the butts that need cleaning up.

Meaning: 'Discarded' means thrown away or no longer wanted, which accurately describes the cigarette butts in question.

Wrong options:

• unguarded: 'Unguarded' means not protected or watched over, which does not relate to the action of throwing away cigarette butts.
• regarded: 'Regarded' means considered or thought of in a certain way, which does not fit the context of the physical state of the butts.
• warded: 'Warded' means protected or guarded, which is not relevant to the act of throwing away cigarette butts.

Correct answer: eyesore

Explanation: The term 'eyesore' is appropriate as it describes something that is unpleasant to look at, which fits the context of cigarette litter in urban environments. It aligns grammatically and contextually with the sentence's focus on the negative visual impact of litter.

Meaning: 'Eyesore' refers to something that is visually unappealing or ugly, particularly in a public space.

Wrong options:

• heartsore: 'Heartsore' refers to emotional pain or sadness, which does not apply to the visual context of litter.
• bedsore: 'Bedsore' is a medical term for a sore caused by prolonged pressure on the skin, which is irrelevant to the context of pollution.
• footsore: 'Footsore' describes pain in the feet from walking, which does not relate to the visual impact of cigarette butts.

Correct answer: potentially

Explanation: The word 'potentially' fits well as it indicates the possibility of contamination occurring, which is relevant to the context of chemicals leaching from cigarette butts. It is grammatically correct and logically conveys the uncertainty of the impact.

Meaning: 'Potentially' means something that could happen or exist, indicating the risk of contamination from cigarette butts.

Wrong options:

• substantially: 'Substantially' means to a great extent or degree, which does not convey the idea of possibility that 'potentially' does.
• deferentially: 'Deferentially' means showing respect or yielding to someone else's opinion, which is unrelated to the context of contamination.
• inertially: 'Inertially' refers to the property of matter to remain at rest or in uniform motion, which does not fit the context of environmental impact.

Correct answer: implementation

Explanation: The term 'implementation' is the correct choice as it refers to the process of putting a decision or plan into effect, which is relevant to the context of the new law. It fits grammatically and contextually, indicating the need to monitor how the law is executed.

Meaning: 'Implementation' means the act of carrying out or executing a plan or law, which is essential for assessing its effectiveness.

Wrong options:

• exploitation: 'Exploitation' refers to taking unfair advantage of something, which does not fit the context of monitoring a law's execution.
• implantation: 'Implantation' refers to the act of inserting something into a body or system, which is not relevant to the context of law enforcement.
• interpretation: 'Interpretation' means explaining or understanding something, which does not relate to the practical execution of the law.