In which country do over 30 million people live in caves?

Which ofbthe following is a characteristic shared by both brazil and mexico

Based on what you know about the location of the earth in relation to the sun, why is this called the goldilocks zone in other galaxies? a. it's a region that exhibits a weak gravitational pull, thus maintaining a safe distance from the sun. b. it's an area that doesn't experience any major weather events that could cause mass extinctions. c. it's an area that's an optimal distance from the sun for potentially supporting life. d. it's a region that's unaffected by asteroid or meteor impacts.

Why slip off slopes are found on the inside of meanders? why river cliffs are found on the outside of meanders?