The right answer is thinking.
The "thinking" is not a reflex, it is a competence that the newborn will acquire a few months after his birth.Studies have shown that babies begin to think 4 months already, they have an idea about the laws of physics. He continues to reconstruct the image he makes of the world according to the latest information he receives.
At 8 months, his brain already models the probability of future action by confronting his memory with the information his senses provide. One of the keys to human intelligence.
Convergent evolution would be the best way to explain why two species that look similar are not necessarily that closely related. In convergent evolution, distinct species develop similar anatomical characteristics after its divergence from one common ancestor that does not possess the initial characteristic.
All of those can potentially harm the earth. Human activity is a cause of pollution, and pollution is the cause of acid rain to some extent.