I believe the answer is: positive externality
Positive externality refers to The benefit that enjoyed by a third party when the first and second party are conducting a transaction.
When you receive a vaccines, you prevent yourself from becoming a host that could contaminate other people from getting the virus. In the example above, you and your children are the first and second party. And other children are the third party.
<span>C) movement from rural areas to urban areas--the late 1800s is a period of urbanization connected to industrialization in the US
The Gilded Age is a period of industrialization which brought large numbers of people from rural areas to the cities to obtain work. More technology made farming easier and less people were needed to farm therefore cities offered a better way of life. </span>
When did the caste system evolve into a four tiered hierarchy?A.) when the Aryans ruled over the region - They arrived in 1500BC and developed the grouping of people based on their status and activities in life.
