Mars has a very similar angle of axial tilt to Earth.
No. Erosion could not have such a dramatic effect on Earth's rotation. The tilt on Earth's axis is likely a result of a collision with another planet early in Earth's history. This same collision formed the moon.
The year.
The equator is defined as zero latitude.
Climate
The Earth's tilt is what causes the seasons.
Earth's axial tilt is 23.44°.
23.5 degrees
Seasons
mostly climate
The earths tilt at its axis
23.5 degrees
Earth's tilt is much older than that - it probably had its tilt for millions of years.
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23.5 degrees
23.5 degrees
It is the result of how the earth was formed.