Estimate these answers by rounding off. a) 1 899: 21
b) 3010 x 299
c) 2 895 x 110
d) 99 020 = 50
e) 200 000 = 25
f) 4 020 X 198​

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.

може ли да зареждате повече информация, моля

answer seismograph;