What must be true for radioactive dating to be possible with a certain sample? O A. The sample cannot contain any radioactive elements.
OB. The sample must contain radioactive elements.
O C. The sample must have no half-life. O D. The sample must have a half-life greater than 1 billion years. SUBMIT

The sample must contain radioactive elements.

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.

b.

developed countries have tended to improve the environment, while developing countries have tended to damage it.