Answer:
I am so simple that I can only point. Yet I guide men all over the world.
I build up castles. I tear down mountains. I make some men blind. I help others to see.
Man walks over, and man swims under. In times of war, it can be burned asunder. What is it?
We are all around, yet to us you are half blind. Sunlight makes us invisible, and difficult to find
The more of them you take, the more you leave behind. What are they?
A word of five letters, Upside down is the same, A shark does this, But itβs not to blame. What is the word?