The transition to the emergence of certain creatures
The cross-era progress of human science and technology and the emergence of the interstellar era. As the birth rate of the population declined, mermaids were developed, plant companions emerged, and the third type of humans emerged. What would the interstellar world be like without a cultural gap?
The first time I traveled through time, I became the first-generation mermaid. Why was the doctor who developed me not even a human? !
When I time travel for the second time, why am I surrounded by a group of men... Where is my doctor? !
Purpose: Protect the environment and don't let the last living things on earth be artificial artifacts