Which country (or countries) has the "youngest" population, that is, the highest proportion of population under age 15?
Which country (or countries) has the "oldest" population, that is, the highest proportion of population over age 64?

Youngest: Niger

1. Niger — 50.12% under 15.

Oldest: Japan

Japan has the highest old-age dependency ratio of all OECD countries – there is one person over 65 for every two people between the ages of 20 and 64.

Explanation:

d. new methods of assembly are introduced.

explanation:

this allows for the goods to be made on a larger scale. not faster because now it is shown to be made better, hence the greater productivity in the question. it is calling for something new to be introduced.

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.