A trade restriction is an artificial restriction on the trade of goods and/or services between two or more countries. It is the byproduct of protectionism.
Niger and Congo are two rivers after which countries are named (actually in both cases two countries each) - and those are African countries, so they must be in Africa.
Zambezi is a river in Angola and Namibia.
Tigris is a River in Mesopotamia, in Asia - so that's the correct answer!
An agronomist, or crop scientist, studies plants and how they can be grown, modified, and used to benefit society. They use science to carry out experiments that create new techniques for agriculture production.
The answer is the first option.
