Avolcanic eruption can be frightening and destructive, but it can also humankind. choose two positive outcomes of a volcanic eruption. 1.valuable metals can be found in ore near a volcano's base. 2.volcanoes emit greenhouse gases into the atmosphere. 3.volcanic ash is rich in minerals and makes for good fertilizer. 4.volcanic emissions improve air quality, those with respiratory problems.

The correct answers are:
1. Valuable metals can be found in ore near a volcano's base
3. Volcanic ash is rich in minerals and makes for good fertilizer
The magma from the volcanoes creates the igneous rocks, which are the hardest rocks, and also rocks predominantly composed by metals, so the volcanoes are a good candidate for finding quality ore.
The volcanic ash contains particles of lots of metals and it enriches the soil and makes it for a nice place to grow plants.

The investiture controversy began as a power struggle between pope gregory vii (1072–85) and henry iv, holy roman emperor (1056–1106).[2] a brief but significant struggle over investiture also occurred between henry i of england and pope paschal ii in the years 1103 to 1107, and the issue played a minor role in the struggles between church and state in france, as well.by undercutting the imperial power established by the salian emperors, the controversy led to nearly 50 years of civil war in germany, and the triumph of the great dukes and abbots. imperial power was finally re-established under the hohenstaufen dynasty. historian norman cantor: