61) Which river forms the Grand Canyon in the United States?
62) Which of these cloud forms is found at the highest altitudes?
63) Thickness of atmosphere around the earth is _________
(A) 100 km
(B) 130 km
(C) 145 km
(D) 195 km
64) Atmosphere around the earth maintain its _________
65) The layers of atmosphere are divided into ________
(A) Two parts
(B) Three parts
(C) Four parts
(D) Five parts
66) Above the earth's surface troposphere extends to a height of __________
(A) 08 km
(B) 12 km
(C) 20 km
(D) 15 km
67) Which next layer is above the troposphere?
68) The mesosphere extended above the earth's surface is upto _________
(A) 60 km
(B) 65 km
(C) 80 km
(D) 85 km
69) Which one of the following phenomena occurs when water vapour condenses around a particle of smoke?
70) Lines joining places of the same earthquake intensity are known as ___________
(C) Isoseismal lines