Carbon dioxide - Carbon dioxide is the only volcanic gas that fits the description. The sulfur gases have bad odors; water vapor could kill only if it were scalding hot; and carbon monoxide is a poisonous gas, but it would change to carbon dioxide in open spaces. In the case above, carbon dioxide seeping upward from a magma chamber had displaced oxygen in the soil around the tree roots and killed the trees (pg 134)
Charlemagne reunited Western Europe. He built an empire that reached across three countries.
Could be a fossil but im not sure. is it multiple choice?
Germany kept attacking us with submarines.