Meaning: A 'component' is a part or element of a larger whole, in this case, referring to nitrogen's role in plant cells.

Wrong options:

• compounds: 'Compounds' is a noun that refers to substances formed from two or more elements, which does not fit as it does not describe nitrogen's role directly in this context.
• severe: 'Severe' is an adjective that describes something very bad or serious, which does not fit grammatically or contextually as it does not relate to nitrogen's role.
• normally: 'Normally' is an adverb that describes the usual manner of something, which does not fit as it does not describe a part of plant cells.
• sends: 'Sends' is a verb that means to cause to go or be taken to a particular destination, which does not fit as it does not describe nitrogen's role in plant cells.
• advance: 'Advance' is a verb that means to move forward in a purposeful way, which does not fit as it does not describe nitrogen's role in plant cells.
• promotes: 'Promotes' is a verb that means to support or actively encourage, which does not fit as it does not describe nitrogen as a part of plant cells.

Correct answer: compounds

Explanation: The term 'compounds' fits grammatically as it is a noun that refers to substances formed from two or more elements. In this context, it describes the organic substances that contain nitrogen, which is essential for plant growth.

Meaning: 'Compounds' refers to substances made up of two or more elements, in this case, organic substances that include nitrogen.

Wrong options:

• component: 'Component' is a noun that refers to a part of something, which does not fit here as it does not describe organic substances.
• severe: 'Severe' is an adjective that describes something very bad or serious, which does not fit grammatically or contextually as it does not relate to organic substances.
• normally: 'Normally' is an adverb that describes the usual manner of something, which does not fit as it does not describe organic substances.
• sends: 'Sends' is a verb that means to cause to go or be taken to a particular destination, which does not fit as it does not describe organic substances.
• advance: 'Advance' is a verb that means to move forward in a purposeful way, which does not fit as it does not describe organic substances.
• promotes: 'Promotes' is a verb that means to support or actively encourage, which does not fit as it does not describe organic substances.

Correct answer: normally

Explanation: The word 'normally' fits grammatically as it is an adverb that describes the usual manner in which nitrogen produces yield responses in crop plants. This aligns with the context of discussing nitrogen's effects on plant growth.

Meaning: 'Normally' means in a usual or typical manner, indicating how nitrogen typically affects crop yields.

Wrong options:

• compounds: 'Compounds' is a noun that refers to substances formed from two or more elements, which does not fit as it does not describe the manner of nitrogen's effect.
• severe: 'Severe' is an adjective that describes something very bad or serious, which does not fit grammatically or contextually as it does not relate to yield responses.
• component: 'Component' is a noun that refers to a part of something, which does not fit as it does not describe the manner of nitrogen's effect.
• sends: 'Sends' is a verb that means to cause to go or be taken to a particular destination, which does not fit as it does not describe the manner of nitrogen's effect.
• advance: 'Advance' is a verb that means to move forward in a purposeful way, which does not fit as it does not describe the manner of nitrogen's effect.
• promotes: 'Promotes' is a verb that means to support or actively encourage, which does not fit as it does not describe the manner of nitrogen's effect.

Correct answer: promotes

Explanation: The word 'promotes' fits grammatically as it is a verb that indicates an action of supporting or encouraging rapid vegetative cultivation. This aligns with the context of nitrogen's role in enhancing plant growth.

Meaning: 'Promotes' means to support or actively encourage something, in this case, rapid vegetative growth in plants.

Wrong options:

• compounds: 'Compounds' is a noun that refers to substances formed from two or more elements, which does not fit as it does not describe an action related to plant growth.
• severe: 'Severe' is an adjective that describes something very bad or serious, which does not fit grammatically or contextually as it does not relate to promoting growth.
• component: 'Component' is a noun that refers to a part of something, which does not fit as it does not describe an action related to plant growth.
• sends: 'Sends' is a verb that means to cause to go or be taken to a particular destination, which does not fit as it does not describe an action related to promoting growth.
• advance: 'Advance' is a verb that means to move forward in a purposeful way, which does not fit as it does not describe an action related to promoting growth.
• normally: 'Normally' is an adverb that describes the usual manner of something, which does not fit as it does not describe an action related to promoting growth.