There are many reasons why they should be classified. For starters, they enable us to understand better what kind of a mark they had on history. They also help us understand how they influenced the society and what exactly was revolutionary about them. The classification helps us understand the events surrounding them and following them and the classification can even help us predict what might happen in the future.
<span>B) He noticed four-fifths of the air had been used up. If by air this question is referring to oxygen, the fact that it has been used up means it has reacted, mean a substance has combusted.</span>
