Explain why history is about the same topic might change over time

The fact that the past changes should not be regarded as a nuisance. It is one of the things historians are interested in. It is also one of the things which make history difficult. But the background situations in history, such as the receptivity of a culture to an idea, can and do change over time.

interdependence is when all participating groups and individuals depend on each other. if you depend on one anothers goods, you end up trading in order to get the items you're looking for. (for ex: if i have food and you have water, we trade in order to depend on each other to live)