Solution:
Caucasian people account for 33% of world population.

Solution:
Khartoum lies on the Nile Rivers. The Nile is composed of two tributaries: the White Nile and the Blue Nile. The White Nile, which is the longer of the two, begins at Lake Victoria in Tanzania and flows north until it reaches Khartoum, Sudan, where it converges with the Blue Nile. The Blue Nile begins near Lake Tana in Ethiopia.

Solution:
'Ninety East Ridge' is situated in Indian Ocean. The Ninetyeast Ridge is thought to have originated from hot spot volcanic activity now located at the Kerguelen Islands near Antarctica.

Solution:
In Italy river Po is found. Po River. Po River, Latin Padus, longest river in Italy, rising in the Monte Viso group of the Cottian Alps on Italy's western frontier and emptying into the Adriatic Sea in the east after a course of 405 miles (652 km).

Solution:
Rice crop needs annual rainfall of about 150 cm, high temperature and humidity. Rice requires high temperature above 200C-350C and high rainfall between 150 to 300 cm. Well drained Alluvial and loamy soil is suitable for the growth of wheat.

Solution:
The Arctic Ocean is the smallest of the world's five ocean basins.

Solution:
The waterfall 'Victoria' is associated with the river Zambeji. Victoria Falls, spectacular waterfall located about midway along the course of the Zambezi River, at the border between Zambia to the north and Zimbabwe to the south.