Answer:
D. tierra caliente, tierra templada, tierra fria, tierra helada.
Explanation:
The Latin American region has its own unique names for the elevation zones based on the climate. The lowest of them is the tierra caliente, characterized with lowlands and hills covered with dense tropical forests, and hot weather. The tierra caliente is the second, located between 1,000 and 2,000 meters, being still part of the tropical climate, but being cooler and more pleasant, which is why there are lot of big cities on this elevation. The tierra fria is located further up, up to 3,000 meters, and it is colder, dominated with grasslands, and the living conditions are not the best. The top elevation zone is the tierra helada, located in the highest parts of the Andes, being dominated by barren mountain slopes, strong winds, and cold climate.
Religious and ethnical problems.
It was one of the largest empires of the world with many different ethnicities. The problem was to unite people under one rule.
Another problem was communication. It was hard to transfer knowledge and news to all parts of the empire because it was too large.
During the early earth, when photosynthesis has not yet evolved, there were only negligible amounts of free oxygen in the atmosphere. It was said that the Earth's atmosphere had no free oxygen then. This is about 3.5 billion years ago.
Muhammadu Buhari, elected in 2015
