The correct answer is - industry.
The developing countries are most often occupied with making the economies heavily focused on the industry, so the countries engage into a big industrialization process.
The industries are usually based around manufacturing of the natural resources that the country has, and most often those are the metal ores, the agricultural products, creating materials...
The developing countries usually have a relatively big economic growth, and that is due to the bad economic basis that they had as a starting point.
Well for starters, we have minerals in our bodies like iron, calcium, magnesium, etc. but we also use it for things like electricity and buildings and cars such as we use copper in electricity, iron to make steel, and so on
A man named Alfred Wegener proposed that all the continents were one, giant continent which he called Pangaea. He backed up this idea with evidence from other fossil remains. Fossils from animals native to a certain country were appearing on other countries from much further away.