When a Mars-sized object hit the Earth.
21,000-26,000 years, caused by wobble of earth about its axis.
The Earth's axis is tilted at an angle of about 23.5 degrees compared to the plane of the Earth's orbit, also called the "ecliptic". As far as we know, it has been at this angle for billions of years; probably since the impact with a "rogue" planet that created the Moon about 4 billion years ago.
Quite a few since it's been around for 6+ billion years.
The seasons are caused by the tilt of the Earth's axis combined with its movement around the SUN.
If you meant "Are the days and nights caused by the earth spinning on it's axis?" then yes, they are.
The seasons are cause by the tilt of the axis of the Earth. The rotation about axis itself moves very little
It is a result of the way the earth is tilted on its axis
Yes.
axis
Yes they are.
Using the definition of revolution around the sun - then as old as the Earth, or about 4.5 billion years. It is essentially unchanged since then. It's rotation around its axis (a day) started later (maybe a quarter of a billion years later) but is constantly slowing down.
yes