Some estimates put the first human settlements in the Amazon at 32,000 to 39,000 years ago. Since that time, Amazon people have developed lifestyles that are well integrated with the benefits and constraints of rainforests.
An estimated 7-10 million Amerindians (the term for American Indigenous peoples) lived in American rainforests, half of them in Brazil, at the time of European arrival. When Pizarro arrived in Peru, more land was under cultivation and more food was being produced in the Andean region than today.
What are the options for the question?
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.
Find greener and a good thing you will get your way