Which of the following statements best describes why most cultures have changed over time? a. all cultures have been colonized by an outside power at one time or another. b. all immigrants abandon their native cultures and assimilate into new ones. c. new elements and ideas are spread and adopted into existing cultures. d. decreased trade and communication have increased connections between people.

The correct answer is - C. New elements and ideas are spread and adopted into existing cultures.

Throughout the history, the different people with different cultures have been communicating with one another. That communication had been limited to a local level, and than with the development on a regional level, and nowadays it is on a global level.

As more and more people have been communicating with each other, the more ideas, perspectives, technologies, have been shared. That has been influencing the cultures and way of life of pretty much everyone around the world, so all cultures, i one way or another, have been changing in order to progress and keep up with the others.

a is the answer i believe.