How much thorium 234 will remain after 3 half lives

In 1933 the 21st amendment was added to the u. s. constitution, allowing for the manfacture, transportation, and sale of alacoholic beverages in the united states. why was this amendment needed?

Stages 1 and 4 of the demographic transition are similar in that

8. compare the education of a sparta boy and an athenian boy. (2 points)