The plant roots containing nitrogen fixing bacteria are
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<u>C.</u><u> </u><u>PEA</u>
Plants of thePea Family known as legumes, are some of the most important hosts for nitrogen-fixing bacteria, but a number of other plants can also harbour these helpful bacteria.
A control group is different because it is not what is being tested. for example the control group would use sugar pills while the other group uses the pills being tested