Unafikiria ni nini itakayokuwa changamoto kubwa ulimwenguni mwaka wa 2050?
Tafadhali orodhesha au panga changamoto tatu kuu. Order the items from the following list. First select an item with the spacebar to show a menu of possible ranking positions. Next, click a ranking position to order it in the ranked list. Note the menu will display more ordering options as you add items to the ranked list.
Drag items from the left-hand list into the right-hand list to order them.