Most of the earliest human civilizations developed in... a
desert regions, with arid climates and plenty of cacti.
b
river valleys, with fertile soil and fresh water for crops and transportation.
c
high mountains and plateaus, with rugged terrain.
d
In the tropics

Given: circle a externally tangent to circle b. how many possible common tangents to circles a and b can exist? 2 3 4

When volcanoes erupt, magma (hot, molten rock) rises toward the surface of the earth. as magma cools, solid rock forms. this rock contains substances from the interior of the earth. which of the following natural resources is likely to be plentiful near subduction zones where volcanic activity has occurred in the past?

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.