(a) 3.6 billion years(b) 4.6 billion years ✅(c) 5.6 billion years(d) 6.6 billion years

(a) Maximum when it is farthest from the Sun(b) Maximum when it is closest to the Sun ✅(c) Remains constant at all points on the orbit(d) Decreases continuously

(a) Isobar(b) Isohyet ✅(c) Isotherm(d) Isoneph

(a) Troposphere ✅(b) Stratosphere(c) Mesosphere(d) Exosphere

(a) Deforestation of large areas(b) Release of chlorofluorocarbons ✅(c) Changes in asteroid activity(d) Release of industrial waste

(a) Tanzania(b) Mexico(c) Mongolia ✅(d) Stratus

(a) Bhutan ✅(b) China(c) Pakistan(d) Mongolia

(a) Coriolis force ✅(b) Gravitational force(c) Centripetal force

(a) Specific humidity(b) Relative humidity(c) Absolute humidity ✅

(a) Cyclone(b) Monsoon(c) Jet stream ✅(d) China