GROUNDWATER is the largest source of freshwater on earth.
An alluvial fan is a triangle-shaped deposit of gravel, sand, and even smaller pieces of sediment, such as silt. This sediment is called alluvium. Alluvial fans are usually created as flowing water interacts with mountains, hills, or the steep walls of canyons.
Also, Marine sediment, any deposit of insoluble material, primarily rock and soil particles, transported from land areas to the ocean by wind, ice, and rivers, as well as the remains of marine organisms, products of submarine volcanism, chemical precipitates from seawater, and materials from outer space.
This Should Help a Little:
A largely semi-arid belt of barren, sandy and rock-strewn land, the Sahel marks the physical and cultural transition between the continent's more fertile tropical regions to the south and its desert in the north. ... The Sahel also suffers from ethno-religious tensions, political instability, poverty and natural disasters.
Answer:
Average life expectancy in most European countries extends well past the age of retirement.
Explanation:
The European Union, or at least most of its members, tend to have relatively good welfare systems. This is the case because of the strong economies of the countries but also because it helps the population, which in turn tends to have positive effects. Some countries are even targeted for migration just because of their generous welfare system.
This situation is very likely to change though as there is a very big chance that the economies of the European countries will not be able to sustain the welfare systems that they currently have. The main reason for this is that the population is aging. With the population becoming older and older, there are more and more people that rely on the welfare system, creating a disbalance in its functioning. On top of that, life expectancy is high and is gradually increasing, meaning that not just more people will rely on the welfare system but also for a longer period of time.
B. The rivers were used to sustain life by growing crops and food and having an unlimited drinking supply.
