Centripetal Force.
Yes.
because they are all spheres!
No but they are of a spherical shape
The Sun, Earth and the Moon are all oblate spheroids. Meaning their equatorial diameter is greater than their polar diameter.
The sun and the moon are spheres... and maybe mountains are cones?
They are being pulled by the force of gravity
no it isn't the earth is a little flattened around the poles A circle is a two dimensional object. I think you mean are they spheres. In general, They are, but not perfect spheres. The equators bulge out slightly
They are imaginary lines drawn on spheres such as the earth, sun, moon, planets to simplify the location of points of interest.
Of Earth's four major spheres atmosphere, hydrosphere, and biosphere are absent or nearly absent on the Moon. This prevents many of the natural processes we see on Earth from happening on the Moon.
Roughly. Anything that spins for incredibly long periods of time (I.E Billions of years) Natuarally becomes spherical, But if you want to be so incredibly accurate, No. Because of all the gaping holes and perilous mountains ect.
The Sun is very big. You could fit about 1,300,000 Earths inside the Sun ( ignoring the spaces between the spheres). The Sun is about 865,000 miles in diameter and the Earth is about 7,925 miles in diameter.
Spherical. They are approximately spheres. The earth is more of an oblate sphere, a squashed sphere - this is due to its spin.