Meaning: 'Fifty percent' refers to half of the total number of flowering plant species.

Wrong options:

• adapt: 'Adapt' is a verb that means to adjust or modify, which does not fit as it does not quantify plant species.
• environmental stability: 'Environmental stability' is a noun phrase that describes a state of balance in ecosystems, but it does not provide a numerical value for plant species.
• use: 'Use' is a noun that refers to the act of employing something, which does not fit as it does not quantify plant species.
• struggle: 'Struggle' is a noun that refers to a fight or effort, which does not relate to the quantification of plant species.
• reduce: 'Reduce' is a verb that means to make smaller or less in amount, which does not fit as it does not quantify plant species.
• perish: 'Perish' is a verb that means to die or cease to exist, which does not fit as it does not quantify plant species.

Correct answer: perish

Explanation: The verb 'perish' indicates the potential extinction or death of ecosystems without pollinators. It fits grammatically as it follows the modal verb 'would' and contextually as it describes the dire consequences of losing pollinators.

Meaning: 'Perish' means to die or cease to exist, particularly in the context of ecosystems.

Wrong options:

• fifty percent: 'Fifty percent' is a noun phrase that quantifies a portion, which does not fit as it does not indicate an action or consequence.
• adapt: 'Adapt' is a verb that means to adjust, which does not convey the idea of dying or ceasing to exist.
• reduce: 'Reduce' is a verb that means to make smaller, which does not fit the context of extinction or death.
• struggle: 'Struggle' is a noun that refers to a fight or effort, which does not convey the idea of dying or ceasing to exist.
• environmental stability: 'Environmental stability' is a noun phrase that describes a balanced state, which does not fit as it does not indicate an action or consequence.
• use: 'Use' is a noun that refers to the act of employing something, which does not fit as it does not indicate an action or consequence.

Correct answer: use

Explanation: The noun 'use' refers to the application or consumption of pesticides. It fits grammatically as it serves as the object of the verb 'reducing' and contextually as it relates to the discussion of pesticide application affecting pollinators.

Meaning: 'Use' refers to the act of employing or utilizing something, in this case, pesticides.

Wrong options:

• adapt: 'Adapt' is a verb that means to adjust or modify, which does not fit as it does not relate to the application of pesticides.
• environmental stability: 'Environmental stability' is a noun phrase that describes a balanced state, which does not fit as it does not relate to pesticide application.
• struggle: 'Struggle' is a noun that refers to a fight or effort, which does not fit as it does not relate to pesticide application.
• reduce: 'Reduce' is a verb that means to make smaller, which does not fit as it does not serve as a noun for the context of pesticide application.
• fifty percent: 'Fifty percent' is a quantifying noun phrase that does not relate to the application of pesticides.
• perish: 'Perish' is a verb that means to die or cease to exist, which does not fit as it does not relate to pesticide application.

Correct answer: environmental stability

Explanation: The phrase 'environmental stability' refers to a balanced and sustainable ecosystem, which is the desired outcome of protecting pollinators. It fits grammatically as a noun phrase and contextually as it encapsulates the goal of the efforts discussed in the passage.

Meaning: 'Environmental stability' refers to a state of balance and health in ecosystems, ensuring sustainability.

Wrong options:

• adapt: 'Adapt' is a verb that means to adjust or modify, which does not fit as it does not describe a state of balance.
• use: 'Use' is a noun that refers to the act of employing something, which does not fit as it does not describe a state of balance.
• struggle: 'Struggle' is a noun that refers to a fight or effort, which does not fit as it does not describe a state of balance.
• reduce: 'Reduce' is a verb that means to make smaller, which does not fit as it does not describe a state of balance.
• fifty percent: 'Fifty percent' is a quantifying noun phrase that does not describe a state of balance or health in ecosystems.
• perish: 'Perish' is a verb that means to die or cease to exist, which does not fit as it does not describe a state of balance.