A.I. Explanation:

Correct answer: hosted

Explanation: The verb 'hosted' is in the past tense, which is necessary here to indicate that Mars may have had life in the past. It fits grammatically and contextually as it aligns with the narrative of Mars potentially having once supported life.

Meaning: 'Hosted' means to have provided a place or environment for something, in this case, life forms.

Wrong options:

• shielded: 'Shielded' is a past participle that describes protection, which does not fit as it does not relate to the concept of providing a habitat for life.
• multiplying: 'Multiplying' is a present participle that indicates an ongoing action, which does not fit the past context of the sentence.
• resulting: 'Resulting' is a present participle that indicates a consequence, which does not fit the context of hosting life.
• obtained: 'Obtained' is a past participle that means to have acquired something, which does not relate to the idea of providing a habitat.
• offered: 'Offered' is a past participle that means to have presented something, which does not fit the context of hosting life.

Correct answer: shielded

Explanation: The word 'shielded' serves as a past participle that describes how the organisms were protected from harmful radiation. It fits grammatically and contextually as it describes the condition of the organisms' environment.

Meaning: 'Shielded' means protected from harm or danger, in this case, from radiation.

Wrong options:

• hosted: 'Hosted' does not fit here as it refers to providing a habitat, not protection from radiation.
• multiplying: 'Multiplying' is a present participle that indicates an ongoing action, which does not fit the context of being protected.
• resulting: 'Resulting' is a present participle that indicates a consequence, which does not fit the context of describing protection.
• obtained: 'Obtained' is a past participle that means to have acquired something, which does not relate to the idea of being shielded.
• offered: 'Offered' is a past participle that means to have presented something, which does not fit the context of protection.

Correct answer: multiplying

Explanation: The word 'multiplying' is a present participle that indicates the ongoing action of the organisms increasing in number. It fits grammatically and contextually as it describes the growth of life forms over time.

Meaning: 'Multiplying' means increasing in number or quantity, referring to the growth of microbes.

Wrong options:

• hosted: 'Hosted' is a past participle that does not fit here as it does not describe an ongoing action of growth.
• shielded: 'Shielded' is a past participle that describes protection, which does not fit the context of growth.
• resulting: 'Resulting' is a present participle that indicates a consequence, which does not fit the context of describing growth.
• obtained: 'Obtained' is a past participle that means to have acquired something, which does not relate to the idea of increasing in number.
• offered: 'Offered' is a past participle that means to have presented something, which does not fit the context of growth.