Meaning: 'Harnessed' means to capture and make use of something, in this case, sunlight.

Wrong options:

• utilised: Utilised is a past participle that means to make use of, but it does not convey the specific action of capturing energy as effectively as 'harnessed.'
• critical: Critical is an adjective that describes something of great importance, which does not fit the action of absorbing sunlight.
• diffused: Diffused is a past participle that means spread out, which does not relate to the action of capturing sunlight.
• converted: Converted is a past participle that means changed from one form to another, which does not fit the context of the initial absorption of sunlight.
• secondary: Secondary is an adjective that refers to something of lesser importance, which does not apply to the action of harnessing sunlight.
• integral: Integral is an adjective that means essential or necessary, which does not describe the action of capturing sunlight.
• symbiotic: Symbiotic is an adjective that describes a mutually beneficial relationship, which does not fit the context of the action being described.

Correct answer: converted

Explanation: The term 'converted' is a past participle that indicates the transformation of energy from one form to another, which is essential in the process of photosynthesis. It fits both grammatically and contextually as it describes the change of sunlight energy into chemical energy.

Meaning: 'Converted' means to change something into a different form or use, specifically referring to energy in this context.

Wrong options:

• utilised: Utilised is a past participle that means to make use of, but it does not specifically indicate the transformation of energy as 'converted' does.
• critical: Critical is an adjective that describes something of great importance, which does not fit the action of transforming energy.
• harnessed: Harnessed is a past participle that means to capture and make use of, but it does not convey the idea of transformation that 'converted' does.
• diffused: Diffused is a past participle that means spread out, which does not relate to the transformation of energy.
• secondary: Secondary is an adjective that refers to something of lesser importance, which does not apply to the action of converting energy.
• integral: Integral is an adjective that means essential or necessary, which does not describe the action of transforming energy.
• symbiotic: Symbiotic is an adjective that describes a mutually beneficial relationship, which does not fit the context of energy transformation.

Correct answer: critical

Explanation: The word 'critical' is an adjective that emphasizes the essential nature of photosynthesis in the growth of plants and oxygen production. It fits grammatically and contextually as it highlights the importance of the process.

Meaning: 'Critical' means of great importance or essential, particularly in the context of photosynthesis.

Wrong options:

• utilised: Utilised is a past participle that means to make use of, which does not fit as it does not describe the nature of the process.
• converted: Converted is a past participle that refers to the transformation of energy, which does not describe the importance of the process itself.
• harnessed: Harnessed is a past participle that means to capture and make use of, which does not convey the significance of photosynthesis.
• diffused: Diffused is a past participle that means spread out, which does not relate to the importance of the process.
• secondary: Secondary is an adjective that refers to something of lesser importance, which contradicts the essential nature of photosynthesis.
• integral: Integral is an adjective that means essential or necessary, but it does not emphasize the critical nature as effectively as 'critical.'
• symbiotic: Symbiotic is an adjective that describes a mutually beneficial relationship, which does not fit the context of describing the importance of photosynthesis.

Correct answer: diffused

Explanation: The term 'diffused' is a past participle that describes the action of oxygen being spread out into the atmosphere. It fits grammatically and contextually as it relates to the process of oxygen release during photosynthesis.

Meaning: 'Diffused' means to spread out or scatter, particularly in the context of gases or light.

Wrong options:

• utilised: Utilised is a past participle that means to make use of, which does not fit the context of oxygen being released into the atmosphere.
• critical: Critical is an adjective that describes something of great importance, which does not relate to the action of oxygen being released.
• converted: Converted is a past participle that refers to the transformation of energy, which does not apply to the release of oxygen.
• harnessed: Harnessed is a past participle that means to capture and make use of, which does not describe the action of oxygen spreading into the atmosphere.
• secondary: Secondary is an adjective that refers to something of lesser importance, which does not fit the context of oxygen release.
• integral: Integral is an adjective that means essential or necessary, which does not describe the action of diffusion.
• symbiotic: Symbiotic is an adjective that describes a mutually beneficial relationship, which does not fit the context of oxygen being released.

Correct answer: integral

Explanation: The word 'integral' is an adjective that signifies the essential role of plants in the ecosystem. It fits grammatically and contextually as it emphasizes the importance of plants in sustaining life.

Meaning: 'Integral' means essential or necessary, particularly in the context of the role plants play in the ecosystem.

Wrong options:

• utilised: Utilised is a past participle that means to make use of, which does not describe the role of plants in the ecosystem.
• critical: Critical is an adjective that describes something of great importance, but it does not convey the essential nature of plants as effectively as 'integral.'
• converted: Converted is a past participle that refers to the transformation of energy, which does not apply to the role of plants in the ecosystem.
• harnessed: Harnessed is a past participle that means to capture and make use of, which does not describe the role of plants.
• diffused: Diffused is a past participle that means spread out, which does not relate to the role of plants in the ecosystem.
• secondary: Secondary is an adjective that refers to something of lesser importance, which contradicts the essential role of plants.
• symbiotic: Symbiotic is an adjective that describes a mutually beneficial relationship, which does not fit the context of describing the role of plants.