How do I know when to use the infinitive of a verb?

You use the infinitive of a verb when you have a verb in either in the first, second, or third form next to another verb or if you have two verbs in a sentence. For example, "vamos a bailar", which means,"let's dance." It is grammatically correct and you are not repeating yourself like you were to say, "vamos a bailamos", which means, "let's we dance", which does not make much sense.

What causes organisms to be so diverse?

There are many key factors that cause organisms to be so diverse on our planet. Different environments allow certain organisms with favorable characteristics for that environment to be able to survive and reproduce. Over time, the successful survival and reproduction of these organisms leads to adaptations that allow these organisms to have better chances of surviving in their environment. There are also other factors that cause diversity such as mutations, predators, and the ability to attract mates.

Why was the battle of Antietam significant during the Civil War?

The battle of Antietam was one of the costliest battles in terms of lives lost to be fought in the Civil War for both the South and the North. This battle showed both sides that this war would not be an easy win for either side and that many would men would lose their lives. This was the first battle that was fought on Union soil. The outcome of this battle was a Union victory. The Emancipation Proclamation was issued five days after the battle.