Step-by-step explanation:
lnternal structure of earth
The size of the earth about 12,750 km in diameter was known by the ancient Greek but it was not until the turn of the 20th century that scientists determined that our planet is made up 3 main layers crust , mantle and core.
External structure of earth
According to the classification according to chemical composition , the Earth is divided into crust , mantle and core in physical behavior it is divided into lithosphere, mesosphere , outer core and inner core.