Nitrogen.
Plants cannot use atmospheric nitrogen directly. Nitrogen from the air must be converted into the different form so plants can absorb it. Thus plants need nitrogen-fixing bacteria to convert atmospheric nitrogen into ammonium, which is available for plants to absorb it.
The normally treated group is called the control. Scientists use control to lessen the effects of variables. The accuracy of the results becomes higher. Control groups can be positive or negative depending on the expectation of a phenomenon that would occur in it.
its geocentric cause Ptolemy supported the idea of the geocentric model
Answer:
C
Explanation:
Most are too small to be seen with the naked eye. so they must be looked at with a microscope
