The more backward a civilization is, the more it trades with others.
a. true
b. false

The answer is false.  A backward would tend to isolate themselves rather seek contact with others.  It still relies on primitive means to survive.  In some cases it would rather take from others than open trade relations with them.  This would then lead to conflict.

the invasive species was introduced due to commercial purpouses, as there was a demand for fur clothes and hence, a business opportunity connected to this product. actually, it was when the nutrias scaped, causing harm to the us ecosystems when they acquired the status of invasive species. in this case they have caused an environmental problem, but it could have affected also economic interests or even human health.