<span>Microevolution refers to changes in the genetic pool
of a species population. The changes in the genes (probably gene and allele frequencies)
are observed over short time periods hence are small changes. This is in comparison
to macroevolution that observes huge changes over longer time periods in the population that warrant that the new populations
is considered to be a new species</span>
During a 30 year period, the yearly frequency of drought is 10%, which is experienced in three separate years.
Additionally, drought is a period where precipitation is below average and thus resulting in prolonged shortages of water supply as far as both ground and surface water are concerned. This can last for several months or even for years.
The chemical formula for water is H2O which means that every molecule of water has 2 atoms of hydrogen (H) and one atom of oxygen (O). Here comes the key part. From the Periodic Table of Elements, one sees that one molecule of oxygen atoms weigh 16 grams.
I apologize if this is not what you meant. If you have further questions just tell me.
