Explanation:

- The passage is about the last mammoths and their preservation.

- The preserved bodies of these mammoths were found in the Siberian tundra.

- The permafrost played a crucial role in keeping their bodies intact.

- The passage mentions research aimed at reviving the mammoth.

- Option 1: Engineers - Typically focus on design and build activities.

- Option 2: Scientists - Involved in biological research and genetics.

- Option 3: Investigators - Usually associated with legal or criminal inquiries.

- Option 4: Doctors - Primarily deal with human and animal health.

Given the context, the most appropriate choice is Scientists, as they conduct research in genetics to revive such species.

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