A.I. Explanation:

Option 1: "different the chemical make-up of each planet is."

Explanation: This option suggests a comparison of the chemical make-up of Mars and Earth. However, the text does not focus on the differences in chemical composition; instead, it emphasizes the similarities in their atmospheres and the potential for Mars to support life, which contradicts the claim of this option.

Option 2: "likely it is that both may support human life."

Explanation: The text highlights that Mars' atmosphere is similar to that of early Earth, suggesting a potential for both planets to support life in the future. This aligns with the writer's intent to demonstrate the possibility of Mars becoming habitable, making this option the correct answer.

Option 3: "useful the minerals may be to man in future."

Explanation: This option implies a focus on the usefulness of minerals on Mars. However, the text does not discuss minerals or their utility; it centers on the atmospheres of Mars and Earth and their implications for supporting life, making this option irrelevant.

Option 4: "possible it is that both will be destroyed one day."

Explanation: This option suggests a comparison regarding the potential destruction of both planets. The text does not address destruction; rather, it focuses on the potential for Mars to support life, which is contrary to the idea presented in this option.