Seasons
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AP Environmental Science › Seasons
Ecosystems experience seasonality differences throughout the year. Some regions experience four seasons, while others only experience two season. Why do we experience seasons on Earth?
tilt of the Earth
gravitational pull of the Sun
global climate change
gravitational pull of the moon
Explanation
The correct response is **tilt of the Earth.**The Earth is tilted at an angle of 23.5 degrees. This tilt allows seasonal differences to exist on the Earth since each region is pointing towards the Sun at different angles throughout the year.
The seasons experienced on Earth are caused by __________.
The 
The varying temperature of the sun during different times of year
Geothermal energy on a biological clock
The elliptical shape of Earth's orbit around the sun
The proximity of the Earth to certain star clusters at moments during the Earth's orbit around the sun
Explanation
Contrary to what many people think, the seasons are caused by the amount of light that the surface of each hemisphere of Earth receives during different parts the year. Because of the tilt of the Earth's axis and its rotation, certain months of the year result in more direct sunlight, but not necessarily because they are closer to the sun. The Northern hemisphere receives less sunlight during some months when the Earth's axis is tilted away from the sun; the resulting season is winter. Each ray of sunlight is spread out over more distance at the poles, whereas the warmest areas (at the equator) get the most direct sunlight. When Earth's axis is pointed towards the sun, the resulting season is summer in the Northern Hemisphere and winter in the Southern Hemisphere.