How is our body able to walk (balance) ?
That happens thanks to a part of the brain. I'm not going to go into details as you can find many articles related to this question on google.
How did humans develop speaking, especially in different languages?
I believe that when we got smart enough to differentiate human made sounds, the humans were already spread across the globe and everyone adopted a different combination of sounds to describe various things.
How did we gain intelligence?
That's a matter of biology, thanks to our evolution, our brains got bigger and therefore our intelligence level raised.
Why do humans seek power if they are smart enough to know that their life will end at some point and there will be no point?
Everyone wants their lives to end knowing that they mattered and that they left something behind.
If humans evolved from apes, who introduced God?
God was introduced by humans to fuel their hope in times of need, they needed to fill their inside emptiness with something. They also used this premise to create some rules(i.e. The 10 Commandments) to maintain order. Or how a TV series puts it "The Gods are men's creation to give answers that they are too afraid to give themselves".
WHAT IS LIFE?
Well, aren't we all trying to figure that out? I believe the meaning of life is different for all of us. You'll have to find the answer to this question yourself.