What was the number of people in
the indigenous
population before the
arrival of the Europeans?

According to researches, the Native population in Americas before the arrival of Europeans was around 100 million people, while some are estimating that it was even more.

Explanation:

Before Europeans arrived in America, many native culture were developing and some were even at their peak.

But when the conquistadores came, they killed a lot of them, while a lot of them died due to diseases that were brought by Europeans.

The population in just a couple of decades fell from 100 millions to just a couple of millions.

b.

developed countries have tended to improve the environment, while developing countries have tended to damage it.