Because the seismic waves in the layers are strengthen when in different materials, like denser layers. So scientists can tell there are different types of layers.
Plants leafs produce oxygen elements easy to human breathing source
The Correct Answer is <span>MOLDOVA
Ex. Moldova Has The Lowest GPD in Western Europe By Having Only 1,872
GPD= 1,872</span>
Answer:
Because it's cheaper to import some foods than to grow them locally (even if they grow well here), and the population is too large to be supported entirely by domestic production.