The use of rivers for irrigation in agriculture began in about .
A.
10,000 BCE
B.
6,000 BCE
C.
2,000 BCE
D.
500 BCE

Aplane cuts a pyramid as shown in the diagram. what is the shape of the cross section? a. a hexagon b. a pentagon c. a square d. a triangle

Read the article about the fraser river, one of the most important rivers in canada. what is the most important species of fish in this river? why are the numbers of these fish declining?

Scientists believe that differences in cause hot, plastic-like rock in the asthenosphere to rise toward earth's surface. a. density c. weight b. magnetism d. composition c. conduction. d. density.