Helium makes up of the sun’s mass? a. less than 1% b. about three-fourths c. about one-fourth d. more than 90%

A, as , to a , as a , is as a. b. c. d.

17. the soil erosion pictured here is the result of what? a. harvesting renewable resources at a rate greater than the sustainable yield b. a mudslide caused by excessive rains c. harvesting renewable resources at a rate lower than the sustainable yield d. the transition between geologic eras and eons

What does the map above tell us about the endemity of typhoid fever