A control group of the experiment is the one in which no treatment or intervention is given. So, in your case, the pea plants in which was not subjected any of the fertilizers, will serve as a control group. This is a negative control. A positive control group is the one in which an established treatment is given, which definitely leads to the production of the desired character. So, in your case, a very good well-known fertilizer which has a positive control on the growth of the pea plant, would serve as a positive control.
The answer is B) change the rate of reaction
Explanation:
Reconstruction was the period in the united states during which the Civil war took place and the laws were made to provide equity to the slaves ending slavery.
The problem arises due to the reunion of the 11 states of the South to the Union which seceded earlier. Slavery was more practised in the Southern states compared to Northern states.
The Republican party did corruption from 1869 to 1877 which allowed due to which they lost their election of 1877.
In 1877, a special electoral commission was established in favour of Hayes and Democrats took benefits of this condition.
When Hayes was selected, he withdrew the federal troops from the South which allowed the Democrats to gain their seats in South and ended Reconstruction.
