Which of the following findings, if true, would weaken the arguments of Scientist 2?
A. The planet Venus was unable to sustain life when atmospheric changes occurred.
B. Studies have shown that, during prehistoric times, Earth’s temperature reached 75° Celsius.
C. It is impossible to create a space colony large enough to support life for long periods of time.
D. Recent scientific models have shown that the earth will not be habitable in 1 billion years.

Scientist 2
The sun will enter its Red Giant phase in about 7 billion years. However, new models suggest that Earth has less than a billion years before atmospheric carbon dioxide levels drop to levels that can no longer support photosynthesis. This would lead to a dramatic temperature increase. Once Earth’s average temperature rises to above 70°C, the oceans will evaporate and Earth’s water sources will be almost completely eliminated. One billion years is not long enough for humans to evolve in order to meet large atmospheric and environmental changes, or to develop the technology needed to make Earth habitable. In a billion years, atmospheric changes will eliminate all life on Earth as we know it. Humans need to accept the reality that advanced life flourishes for only a limited period of time. Science fiction—inspired plans to create space colonies or massive sunshades are unrealistic and will not likely be developed in the next billion years.