What is the average density of crust?

Average density of crust is 2.7g/cm^3.

Who's the "Father of Geography"?

"Father of Geography"
A. Aristotle
B. Ptolemy
C. Eratosthenes

D. Kepler

Ans. : Born in Cyrene, in what is now Libya, in 276 B.C., Eratosthenes is commonly called the "father of geography" for he was the first to use the word geography and he had a small-scale notion of the planet that led him to be able to determine the circumference of the earth.

"father of geography"