In volcanic rock does the proportions of iron oxide increase when silicon dioxide increases?

THe amount of iron oxide decreases as the level of silica increases.

Hello

Tundras are among Earth's coldest, harshest biomes. Tundra ecosystems are treeless regions found in the Arctic and on the tops of mountains, where the climate is cold and windy and rainfall is scant. Tundra lands are snow-covered for much of the year, until summer brings a burst of wildflowers.

If you don't believe me you can look up the question and it will show the same info. This is what the website is 

Explore the World's Tundra - National Geographicwww.nationalgeographic.com/environment/habitats/tundra-biome/

And if I wasn't soposted to do this you can report me its just because in new here

 
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