19.The Alkali and Alkaline Earth metals belong to which columns, respectively? a. Column IA & IIA
b. Column VIIA & Column VIIIA
c. Column IIIA & IVA

it HAS to be b or d I mostly think b

i am going to put the answers in order i dint feel like typing it out so yeah

a

d

c

b

b

b

a

d

a

b

c

c

c

b

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.