Puzzle 2 (Biology)
Finally, people invented the time machine. For technical reasons, it can go only 500 Myrs in the past and back. It has another unfortunate limitation: one can go back in time only to the same point in space. However, the Solar system moves through the Galaxy, and there is also cosmic expansion. Because the trajectory is somewhat chaotic, finding the right Earth is not a trivial task, but the first expedition, after much searching, found the system that looked very much like our own and they landed on the planet. But is this planet our Earth? The astronomy cannot help, because it can only locate the Sun approximately. The animals they find do not look like any known fossil. The biochemistry is familiar, but who knows: may be it is just a coincidence. Nothing looks quite like the reconstructions in the textbooks. It may be our Earth, or it may not. The expedition has a biologist, and he thinks he can find the answer.
What is his plan?
What is his plan?