Why is it important to control all of the variables except one in an experiment?

Subduction zones occur on earth where dense oceanic crust dives under more buoyant continental crust. these boundaries are characterized by a deep ocean trench next to a high continental mountain range, large numbers of earthquakes and volcanoes. all of this is further evidence for the a) big bang theory b) origin of the species eliminate c theory of plate tectonics d theory of natural selection 4 sedimentary rocks found high in the himalayen mountain

Which compound contain an iron with a 3+ charge

To calculate percent by mass, use the equation below: calculate the percent by mass of each element. %n = % %h = % %o = %