Calculating the circumference of an ellipse is complicated, but you can approximate Earth's path as a circle, since it is quite close to one. So, just multiply the average Earth-Sun distance by (2 x pi).
Earth travels in an ellipse around the sun
Yes.
It is called an orbit
The path that the Earth takes around the Sun is called its' orbit.
Orbit
The Earths Orbit.
Orbit
It's almost a circle, but actually it's an ellipse.
It's almost a circle, but actually it's an ellipse.
Yes. Gravitational attraction from other objects - mainly the other planets - will gradually change this path.
Earths orbit around the sun is not unusual.
path of planet around the sun