Given Earth's evolutionary timeline, what percent of Earth-like planets in a 2 billion-year-old star cluster can be estimated to host intelligent life?
A) 0 percent
B) 10 percent
C) 30 percent
D) 50 percent
E) 100 percent

Question

Quizplus · Accepted Answer

Intelligent life on Earth took about 4.5 billion years to develop. A 2 billion-year-old star cluster is likely too young for intelligent life to have evolved, making the probability close to 0 percent.

Given Earth's Evolutionary Timeline, What Percent of Earth-Like Planets in a 2