<span>Erosion by rivers is a main valley-forming
process; other processes, such as movement of the earth's crust and
glaciers, also have an important part in some cases. The rate at which a
river deepens its valley depends on several factors.</span>
The fossil range can simply be defined as the time period in which an organism has existed, thus left fossil traces of its existence. The fossil range can be very short, medium, or long, thus usually there are limitations before certain type of organism evolves into another species, thus eliminating the ancestral organism from the fossil records. On the other hand, there are organisms that have incredibly big fossil ranges of several hundred million years, and since they emerged, they have remained almost unchanged. Those kind of fossil ranges are very rare though, and they don't represent the general picture. Most of the fossil ranges are between several thousand years and several million years, as that is usually how much a species exists, ending its reign, be it because of competition, changes in the environment, or big natural disaster.
<u>Soviet Union in Russia used to be a communist country. When the USSR collapsed these early reforms failed to revive the increasingly-stagnant Soviet economy, with productivity growth falling below zero by the early 1980s. This ongoing poor economic performance led to a more radical set of reforms under the leadership of Mikhail Gorbachev. So after they collapsed things go bigger and better, and is leader to almost pure market, but is mixed today.</u>
<u>I you can or want to, brainliest please</u>
Mexico City, Mexico.
Guatemala City, Guatemala.
Belmopan, Belize.
Tegucigalpa, Honduras.
San Salvador, El Salvador.
San José, Costa Rica.
Managua, Nicaragua.
Panama City, Panama.
