In particular, the continents are almost the only source for some key elements such as iron.

In some materials, such as iron, the atoms will line up.

He combines this with the use of materials modern for his time, such as iron.

Other architects had to deal with a lack of proper materials, such as iron.

The province has many material resources such as iron and nickel.

It is almost always made of metal, such as iron or aluminum.

In a few materials, such as iron, they do stay lined up.

If your food had other metals such as iron in it, that would be left too.

Do not get enough vitamins or minerals in your diet, such as iron.

The second example concerns the availability of resources such as coal and iron.