Meaning: Sustainable refers to methods that can be maintained without depleting resources or causing harm to the environment.

Wrong options:

• tricky: 'Tricky' is an adjective that describes something difficult or complicated, which does not fit the context of methods for pest control.
• exposing: 'Exposing' is a gerund that implies revealing something, which does not appropriately describe methods for pest control.
• pressing: 'Pressing' is an adjective that indicates urgency, but it does not describe the nature of the methods themselves.
• identifying: 'Identifying' is a gerund that refers to the act of recognizing, which does not fit as a descriptor for methods.

Correct answer: pressing

Explanation: The term 'pressing' serves as an adjective that conveys urgency, fitting well with the context of the sentence which discusses a worldwide concern in agriculture.

Meaning: Pressing means urgent or requiring immediate attention.

Wrong options:

• tricky: 'Tricky' does not convey urgency and instead suggests difficulty, which is not appropriate in this context.
• sustainable: 'Sustainable' describes methods rather than the urgency of the concern, making it an incorrect fit here.
• identifying: 'Identifying' is a gerund that does not convey urgency and does not fit grammatically as an adjective in this context.
• developing: 'Developing' is a gerund that refers to the process of creating, which does not describe the nature of the concern.

Correct answer: developing

Explanation: The word 'developing' is a gerund that fits grammatically as it describes the action of creating less toxic pesticides, aligning with the context of the sentence.

Meaning: Developing refers to the process of creating or improving something, in this case, pesticides.

Wrong options:

• sustainable: 'Sustainable' is an adjective that does not fit as a gerund and does not describe the action of creating pesticides.
• pressing: 'Pressing' is an adjective that does not convey the action of creating or improving pesticides.
• exposing: 'Exposing' implies revealing something, which does not fit the context of creating pesticides.
• identifying: 'Identifying' refers to recognizing something, which does not relate to the action of developing pesticides.

Correct answer: avoid

Explanation: The word 'avoid' is a verb that fits grammatically as it indicates the action of preventing something from happening, which is relevant to the context of not harming beneficial insects during pesticide application.

Meaning: Avoid means to keep away from or prevent something from occurring.

Wrong options:

• exposing: 'Exposing' implies revealing something, which does not fit the context of preventing harm to beneficial insects.
• developing: 'Developing' is a gerund that refers to the process of creating, which does not fit the action of preventing harm.
• pressing: 'Pressing' is an adjective that does not convey an action and does not fit in this context.
• identifying: 'Identifying' refers to recognizing something, which does not relate to the action of preventing harm.