How many sinkholes happen in a year?

Explore the ways that boundaries influence identity, interaction and exchange. things to consider: what is the race/ethnicity. how easy is it to interact/trade with others.

Venezuela’s economy relies most heavily on which of the followingvenezuela’s economy relies most heavily on which of the following? a. oil reserves in places such as the eastern llanos b. cattle ranching in the grasslands c. fertile farmland in the andean highlands d. coffee plantations in mountainous areas

What is the thickest layer of earth called?