A mutation that happens only on one point of the gene
The right answer for the question that is being asked and shown above is that: "d. A piece may only move into an unoccupied square." a rule in checkers is that d. A piece may only move into an unoccupied square.
From 1860 to 1895, the United States experienced advances in technology, the industrial revolution and the Mexican-American war.
It can't be the Spanish American war because that didn't happen until some years later. It can't be an agrarian revolution because this is during the INDUSTRIAL Revolution and education at the time wasn't prioritized as much as it is today.
