Experimental investigations<span> involve a process in which a "fair test" is designed and variables are actively manipulated, controlled, and measured in an effort to gather evidence to support or refute a </span>causal relationship<span>. Experimental investigations have a control group which does not receive any treatment. A classic example is "What is the effect of light color on plant growth?" In this experiment, the variable color of light is changed by the student. The student may compare red light to green light to natural light.
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Answer: The geologic time scale is the “calendar” for events in Earth history. It subdivides all time into named units of abstract time called—in descending order of duration—eons, eras, periods, epochs, and ages.
Explanation: I learned about it the other day
They are the same easily answer metals all the way
The correct answer is c.
answer b is incorrect <span />
For every 3 Fe there is only 1 Fe3O4 producing.
So, ratio would be: Fe3O4 / Fe = 1 / 3
In short, Your Answer would be: 1 : 3
Hope this helps!