Answers

2014-07-03T19:47:36+05:30
'''Day and night:'''
The Earth rotates on an axis. When it rotates, half of the Earth is exposed to the sun and half is not. When a part of the earth is exposed to the sun it is ''day'' and when it is not exposed to the sun it is ''night.'' Pretty simple. 


'''The seasons:'''
axis------> / 
Earth--> (/)-------O<--Sun 
axis----> / 

Earth's axis is tilted so in summer (for the Southern Hemisphere) the Southern Hemisphere is in the sun longer than the Northern Hemisphere. 
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2014-07-03T19:51:41+05:30
The days and nights occur due to rotation.
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due to rotation of earth around its own axis from west to east in anti-clockwise direction .