The common problem of the research investigating the massed vs. the distributed practice is the <u>lack </u><u>of a </u><u>retention </u><u>or </u><u>transfer test</u>.
The research which intends to investigates the massed refers to one that targets a large population at a time
The research which intends to investigates the distributed refers to one that target the different section of the large population
However, the common limitation of the two research is lack of a retention or transfer test in the investigation.
Therefore, the Option A is correct.
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Answer:
John Wilkes Booth because he was mad that the South had lost.
He also wanted revenge to the Confederate states.
Cause by the end they started to notice that colored people started to get more powerful and there protest got stronger. :D