Meaning: 'Adulthood' refers to the stage in life when an organism is fully developed and capable of reproduction.

Wrong options:

• already: The word 'already' is an adverb that indicates something has happened before a certain time, which does not fit the context of a life stage.
• assumed: 'Assumed' is a verb that does not fit grammatically as it does not represent a life stage and does not follow the structure required here.
• perfect: 'Perfect' is an adjective that does not fit as it does not denote a stage in the life cycle of ants.

Correct answer: pass

Explanation: The verb 'pass' fits grammatically in the present tense and contextually indicates the action of young ants moving through the pupal stage. It aligns with the subject 'young ants' and maintains the sentence's flow.

Meaning: 'Pass' means to go through or move from one stage to another.

Wrong options:

• forming: The word 'forming' is a gerund that does not fit the context of the sentence as it implies an action that is not relevant to the movement through the pupal stage.
• critical: 'Critical' is an adjective that does not fit as it does not describe an action related to the pupal stage.
• already: 'Already' is an adverb that does not convey an action and does not fit the grammatical structure of the sentence.
• assumed: 'Assumed' is a verb that does not fit the context of the sentence as it does not relate to the action of moving through a stage.
• social: 'Social' is an adjective that does not fit as it does not describe an action related to the pupal stage.
• perfect: 'Perfect' is an adjective that does not convey an action and does not fit the grammatical structure of the sentence.

Correct answer: forming

Explanation: The gerund 'forming' fits grammatically as it follows the preposition 'without,' indicating the action that young ants do not engage in during the pupal stage. It logically completes the thought about the absence of cocoon creation.

Meaning: 'Forming' refers to the act of creating or developing something, in this case, a cocoon.

Wrong options:

• pass: The word 'pass' is a verb that does not fit the context of the sentence as it does not relate to the action of creating a cocoon.
• critical: 'Critical' is an adjective that does not fit as it does not describe an action related to cocoon creation.
• already: 'Already' is an adverb that does not convey an action and does not fit the grammatical structure of the sentence.
• assumed: 'Assumed' is a verb that does not fit the context of the sentence as it does not relate to the action of creating a cocoon.
• social: 'Social' is an adjective that does not fit as it does not describe an action related to cocoon creation.
• perfect: 'Perfect' is an adjective that does not convey an action and does not fit the grammatical structure of the sentence.

Correct answer: critical

Explanation: The adjective 'critical' fits grammatically as it describes the noun 'forms,' indicating their importance in the context of ant communities. It logically emphasizes the necessity of these forms for community structure.

Meaning: 'Critical' means essential or of great importance.

Wrong options:

• forming: The word 'forming' is a gerund that does not fit as it does not describe the importance of ant forms.
• already: 'Already' is an adverb that does not fit the context of describing the importance of ant forms.
• assumed: 'Assumed' is a verb that does not fit as it does not describe the importance of ant forms.
• social: 'Social' is an adjective that describes a type of community but does not convey the importance of the forms themselves.
• perfect: 'Perfect' is an adjective that does not fit as it does not convey the critical nature of the ant forms.

Correct answer: social

Explanation: The adjective 'social' fits grammatically as it describes the noun 'communities,' indicating the type of communities formed by ants. It logically completes the thought about the nature of these communities.

Meaning: 'Social' refers to the organization and interaction of individuals within a community.

Wrong options:

• forming: The word 'forming' is a gerund that does not fit as it does not describe the type of communities.
• critical: 'Critical' is an adjective that describes importance but does not fit as a descriptor for the type of communities.
• already: 'Already' is an adverb that does not fit the context of describing the nature of communities.
• assumed: 'Assumed' is a verb that does not fit as it does not describe the type of communities.
• perfect: 'Perfect' is an adjective that does not fit as it does not convey the nature of the communities.