3 is the answer because they play a key role in the nitrogen cycle.
It's cheap, it's easy, and all the cell has to do is sit there and let the molecules diffuse in. ... suppose the sugar glucose is more concentrated inside of a cell than outside ... If sodium ions are outside of a cell, they will tend to move into the cell based .... by building up a high concentration of potassium ions inside the cell, which ...
Answer:
a.The amount of noise
Explanation:
The dependant variable is the variable that changes when the science teacher leaves.
Independant variable would most likely be whether or not the science teacher is in the room.
Hope this helps!
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