What substance in the upper atmosphere blocks ultraviolet radiation from the sun, making life on land possible?
a. methane
b. ozone
c. water vapor
d. carbon dioxide

(B) Ozone

Explanation:

 Ozone is the type of substance which is present in upper atmosphere. The ozone layer is the basically blocks the ultraviolet radiation which is comes from the sun and it is the combination of single molecule with the 3 oxygen atoms.

The ozone layer absorb the ultraviolet radiation and also prevent from the harmful radiation. It helps in make the life possible on the surface of earth. On the other hand, all the options are incorrect as they do not prevent from the UV radiation.

Therefore, Option (B) is correct.

since there isn't any suggested answers i will give you the reason and hopefully you can figure it

south africa, or rather all of africa, has not been in the location in which it is nowadays throughout the geological past. after the super-continent pangaea started to break apart, gondwanaland, in which was africa, moved further south, and parts of it came to be very close to the south pole. because the climate in this part of the world is very cold due to the very dispersed sun rays in there, what is now south africa, started to freeze, and the conditions were right for the formation of glaciers. the glaciers existed up until the period when gondwanaland started to break apart and what is now africa started to move towards north, sp it warmed up and the glaciers melted.

the correct answer would be true friction causes the faults to slip or collide