The brain. Modern homo sapiens such as humans have much larger brain than the early homo sapiens due to the fact that food at the time was becoming scarce so the need for the homo sapiens to become smarter was a necessity. And because of this early homisapiens brains evolved to become much larger than what they were before
Compared to time in earth's history before humans appeared, rates of soil erosion are "higher", due mostly to the fact that some human activity associated with building structures adds to this erosion.
Answer:
The literal meaning of perestroika is "reconstruction"