Because that's the way gravity works.
If you take Newton's formula for the gravitational force, and if you know enough
geometry and calculus to be able to massage and manipulate and excercise it,
you discover that if the central body's mass is huge enough (like the sun), then
the time it takes smaller things to revolve around it depends only on the distance
of the orbit, nothing else. The farther an orbiting object is from the central body,
the longer an orbit takes.
Moons are approximately spherical objects which orbit planets and are smaller than the planets that they orbit, although they are still relatively large objects (so an orbiting dust particle does not qualify as a moon). Since moons orbit planets, their motion around the solar system is controlled by the planets that they orbit; planets orbit the sun, and planets take their moons with them.
The outer planets take longer.
The outer planets take longer to orbit the Sun, because they are farther away from the Sun. It make its gravitational pull weaker to the farther planets. That means that the outer planets take longer to orbit the Sun.
Saturn orbits the Sun like the other planets, it does not orbit anything else. One orbit for Saturn takes 29.4571 Earth years.
Yes, a year is the time it takes a planet to complete one orbit around the sun. This is also known as the orbital period. Different planets have different orbital periods based on their distance from the sun.
Planets do not take steps. Each planet has its own orbit and is is different.
Elliptical Orbit
No. The planets all orbit the sun at the same time. The planets occupy different orbits at different distances from the sun so they do not affect one another significantly.
ORBIT
A fair amount, though it depends on the distances of the planets and their masses. The important thing is that the gravity (and therefore mass) of the central sun must be much greater than that of the planets, other wise they would orbit each other (or the sun would orbit the planet if its mass was much greater).
Halley's Comet takes 73.5 years to orbit the sun but every comet is different just like planets.
Some planets rotate faster or than others. Also the planets take different times to orbit the Sun.
It takes one year for Earth to orbit the sun. Other planets have different orbital periods depending on their distance from the sun.
Moons are approximately spherical objects which orbit planets and are smaller than the planets that they orbit, although they are still relatively large objects (so an orbiting dust particle does not qualify as a moon). Since moons orbit planets, their motion around the solar system is controlled by the planets that they orbit; planets orbit the sun, and planets take their moons with them.
"No"
they are farther away
The outer planets take longer.