Solution:German-Russian botanist and climatologist Vladimir Kop- pen presented a descriptive classification of the world's cli- mate in the year 1884, which was revised and refined in the Years 1918, 1931 and 1936. Koppen has considered veg- etation as the true indicator of climate.This has made the five vegetation zones of the world proposed by candol in 1874 AD the basis of the division of the world's climate. Later, like Koppen, Thornthwaite also propounded that veg- etation is an indicator of climate and the amount of rainfall and temperature have a substantial effect on vegetation, but took evaporation into account.
On this basis, thornthwaite has given importance to precipitation effectiveness in de- marcation of climate. Thornthwaite has accepted vegetation as an indirect element of climate.