How do factors, such as trade, war, migration, and inventions, affect cultural change

I think these factors affect cultural change because it affects the way people live their lives.  In the past, trade is one of the ways how people learn to barter and introduce their culture to other nations. Through trade, people were able to experience the food and products of the people from the other side of the world. While war affects culture in a way where people believe that their culture is superior compared to other culture. 

Cis correct i think

C) to ensure each new cell has an exact copy of the dna