Answer:
from which. Hope you understand me
Initially, people's believe about the ocean floor was that it is mostly flat, and that it has little to no distinguishing features. This was proven wrong when sonar was used to map the ocean floor by <span>German scientists in the early </span>20th century, and they observed that the ocean floor is varied and it showcases such distinguishing features as atolls, submarine canyons, and mid-ocean ridges.
The second largest city in Brazil is Rio de Janeiro, while the third biggest is the capital Brasilia. Rio de Janeiro has an estimated population of around 6,5 million people while Brasilia has little less than 3 million. This makes Rio de Janeiro more than twice bigger in population than the capital of Brazil, Brasilia. But there's something interesting in here in the background, in the past 6 years the population of the second Rio de Janeiro has only increased by little over 9%, while Brasilia's population has increased by around 20% which is more than twice in increase, so if that trend continues in the coming few decades Brasilia will come on top of Rio de Janeiro very quickly.
The answer is 2. The fact that mechanized agriculture has replaced manual labor. Hope this helps :)
