What are the 2 reasons why in the last 200 years we've gone from 1 billion humans to 8 billion humans on planet earth?

Which soil layers comprise the topsoil? o horizon a horizon b horizon c horizon

All of the following are reasons why deserts extremely susceptible to wind erosion except a. they lack major root systems b. they contain thin, dry soil c. they have very few plants and trees d. they are extremely hot and lack water

Arow of elements on the periodic table is called an