How are clouds formed ? Name the four main types of clouds and explain there characteristics in brief.

Clouds are created when water vapor turns into water droplets. Water droplets are tiny particles that float in the air.

Cumulus - Fluffy clouds that have flat bases
Cirrus - Short detached hair like clouds that are found at high altitudes
Nimbus - Cloud that has rain or snow falling from it
Stratus - Flat featureless clouds that are found at low altitudes

Migration people get up and go cause they feel it is best for them 

Answer the use of flood plains and irrigation;