what does it consist of?
Nitrogrn, oxygen, argon, carbon dioxide and small amounts of other gases.
Composition
By volume, dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. 
the general surface wind circulation associated with the high-pressure center (h) is most likely A high-pressure area, high ,or anticyclone. how is it formed? Winds within high-pressure areas flow outward from the higher pressure areas near their centers towards the lower pressure areas further from their centers. Gravity adds to the forces. The winds are further twisted due to Coriolis effect. could i know more about the effect mentioned above? This is an apparent, but fictitious, force that arises when an observer is in a rotating reference frame, due to the conservation of angular momentum of the air as it moves towards or away from the Earth's axis of rotation. how is it related to the wind conditions? They are associated with light winds at the surface and subsidence through the lower portion of the troposphere. what is the last term used above? It is the lowest layer of earth's atmosphere.
t contains 75% of the atmosphere's mass and 99% of the total mass of water vapour and aerosols. It contains 75% of the atmosphere's mass and 99% of the total mass of water vapour and aerosols. It contains 75% of the atmosphere's mass and 99% of the total mass of water vapour and aerosols
Troposphere Troposphere Troposphere
Introduction Introduction Introduction
 It contains 75% of the atmosphere's mass and 99% of the total mass of water vapour and aerosols. The average height of the troposphere is in the tropics, in the middle latitudes, and in the polar regions in winter.  It contains 75% of the atmosphere's mass and 99% of the total mass of water vapour and aerosols.  . It contains 75% of the atmosphere's mass and 99% of the total mass of water vapour and aerosols. 
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Troposphere [SEP] Composition
By volume, dry air contains 78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor. Except for the water vapor content, the composition of the troposphere is essentially uniform. The source of water vapor is at the Earth's surface through the process of evaporation. The temperature of the troposphere decreases with altitude. And, saturation vapor pressure decreases strongly as temperature drops. Hence, the amount of water vapor that can exist in the atmosphere decreases strongly with altitude and the proportion of water vapor is normally greatest near the surface of the Earth.