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.
Answer:
B. Aerobic bottom water
D. High organic productivity in the overlying oxygen rich water
Explanation:
A Shale is a sedimentary rock usually formed from silt and clay-size mineral. There are different colors of Shale. The Black Shale is formed under anaerobic conditions. This means that oxygen is deficient in the water where the Shale forms.
A little amount of organic materials is required for the formation of Black Shale and because Black Shale is formed in an environment lacking oxygen, an oxygen-rich water would not be necessary for its growth. Sediments are necessary in the formation of Black Shale.
