Scientists created the first geologic column by determining the relative ages of sedimentary rock in
a)one chosen area
b) the area where life began
c)north america
d)areas all over the world

they are both synthetic elements

explanation:

d

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

i think   the answer is c hope i'm right