History of Peroidic table

History OF Periodic Table and Mendeleev''s Periodic Table

Third peroid of th periodic table contains the following number of elements.

Metamorphosis in the life history of Periplaneta is

Life history of Cockroach belongs to

History Of Communiction

Distinguish between the arrangement of elemens in Medeleev's peroidic table and Modern periodic table. Which of the two arrangements of elements is better and why ?

The geological history of earth closely correlates with the biological history of earth. True/False

In the life history of cockroach (Periplaneta) there is :