Meaning: 'Contribute' means to help cause or bring about something, in this case, the increase in plant pollen levels.

Wrong options:

• access: The verb 'access' means to obtain or make use of something, which does not fit the context of causing an increase in pollen levels.
• subject: The verb 'subject' means to bring under control or to expose to something, which does not convey the intended meaning of causing an increase in pollen.
• compare: The verb 'compare' means to examine similarities and differences, which is irrelevant in this context where an action of causing is needed.

Correct answer: trigger

Explanation: The verb 'trigger' is appropriate as it indicates the initiation of health effects, fitting grammatically and contextually with the sentence about pollen being an allergen.

Meaning: 'Trigger' means to cause something to happen, particularly in the context of health effects like allergies.

Wrong options:

• defend: The verb 'defend' means to protect or support, which does not relate to causing health effects from pollen.
• meagre: The adjective 'meagre' refers to something lacking in quantity or quality, which does not fit the context of health effects.
• deduce: The verb 'deduce' means to arrive at a conclusion through reasoning, which is not relevant to the context of causing health effects.

Correct answer: suffering

Explanation: The gerund 'suffering' fits grammatically as it describes the ongoing state of adults experiencing hay fever, aligning with the context of reporting health issues.

Meaning: 'Suffering' refers to experiencing pain or distress, particularly in relation to hay fever in this context.

Wrong options:

• suffered: The past tense 'suffered' does not fit as it implies a completed action rather than an ongoing condition being reported.
• survived: The verb 'survived' means to continue to live or exist, which does not relate to experiencing hay fever.
• surviving: The gerund 'surviving' implies ongoing existence but does not convey the experience of distress related to hay fever.

Correct answer: economic

Explanation: The adjective 'economic' is suitable as it relates to costs associated with health effects, fitting both grammatically and contextually within the sentence about financial implications.

Meaning: 'Economic' refers to matters related to the economy or financial aspects, particularly costs incurred due to health issues.

Wrong options:

• mental: The adjective 'mental' pertains to the mind and does not relate to financial costs, making it contextually irrelevant.
• technological: The adjective 'technological' relates to technology, which is not applicable in the context of health-related costs.
• psychological: The adjective 'psychological' pertains to mental processes and does not fit the context of financial costs associated with health effects.