Does Intelligent life exist on other planets and have they visited earth?

It's a valid question, and it also has an interesting answer. There's probably not "billions" of species out there (the upper estimates are about 100 million or so). And you're right, only one of them is intelligent.

What does this tell you? It really says that intelligence isn't really necessary for a species to survive! Most species survive just fine without anything like our intelligence- remember that for a species to survive, all it really needs its members to do is eat food, avoid being eaten, and have children before they die, which most species do just fine without intelligence.

Remember that evolution is not about making species "better", it's about adapting them to survive so they can pass their DNA on to the next generation. It comes up with all kinds of clever way to do this, but what's important is they are able to keep reproducing, not necessarily stronger, faster, smarter, etc. If a species is doing just fine on its existing level of intelligence, it doesn't need to evolve any more- powerful brains like ours also use up lots of energy so you need to eat even more food to survive, so "too much" intelligence without a good justification isn't always a good idea. So as to why we did evolve intelligence, it's basically this: we evolved from apes, who were already on the smarter side of the spectrum.

Remember I said that there are various ways for species to survive? One of them is to exist in larger social groups, which is what apes do- this helps protect the individual members and it also enables them to take down other animals and the like that individuals might not be able to on their own- this can help compensate for physical weakness. The catch is that these more social animals usually have to be smarter to do this, because working in groups like this involves more complicated behaviours.

So our ancestors were already pretty high up there, and some populations basically just followed an evolutionary path towards even greater intelligence, and that's where humans came from. Scientists suspect a massive drought in Africa at the time might have been what caused this- in those tough conditions, extra strength probably would not have helped much, but being smart enough to find new water sources, conserve water etc, probably would have been.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.