D. All of these
As the bridges and roads created pathways for them to trade and travel, which made it a lot easier and faster for them to do so
To produce isolated colonies of an organism on an agar plate
It was primarily the "Open Door Policy" that opened relations between china and the united states, since this made it possible for many western countries to engage in trade with China.
The first ten amendments to the Constitution that safeguard the rights of individuals are called the "Bill of Rights," since many Americans feared that the new Constitution would be too "powerful".
