(31) . Green house effect is mainly caused by excess of ..... in the atmosphere?
Carbon dioxide
Carbon monoxide
Nitrogen
Hydrogen sulfide
(32) . Which of the following is a chemical reaction?
Rusting of iron
Tempering of iron
Bending of iron
Melting of iron
(33) . Echoes are produced due to?
Reflection of sound
Refraction of sound
Diffraction of sound
Polarization of sound
(34) . 'Gobi Desert' is located in?
Pakistan
Mongolia
Iran
Kazakhstan
(35) . Which of the following districts of Baluchistan contains huge deposits of Copper?
Loralai
Sibi
Khuzdar
Chagi
(36) . Taurus Mountains are a mountain complex located in?
Iran
Turkey
Pakistan
Afghanistan
(37) . The capital city of Zimbabwe is?
Mutare
Harare
Bulawayo
Kadoma
(38) . Which of the following river is formed by the confluence of Euphrates and Tigris?
Jordan
Shatt-al-Arab
Yarmouk
Khabur
(39) . Thomas Jefferson was the ..... president of the United States?
(40) . Formosa is the old name of?
Cambodia
Rhodesia
Taiwan
Bangkok