Has Earth's atmosphere always had the same composition if so what are the causes of it change?

what causes all of the changes that take place in earths atmosphere is the tilt of the earths axis

The meteoroid heats up and sometimes breaks throught the atmosphere

A meteoroid will enter Earth's atmosphere when pulled in by Earth's gravitational pull.

Yes it does. It causes global warming.

Atmospheric friction causes a buildup of heat that vaporizes it.

Gravity. And the meteor is on a path that intersects the orbit of the Earth.

As you go higher in the atmosphere the gases start to compose or join together which causes them to change since there is mixture of more than one gas. Sometimes they form a different element when certain gases form.

Impacts by meteors are the source of craters on the Moon. As there is no atmosphere on the Moon, the meteors do not burn up as happens in Earths atmosphere.

As the gases go higher in the atmosphere they start to compose or join together at some point which causes them to change since there is mixture of more than one gas, sometimes they form a different element when certain gases form

It is not, because the greenhouse affect causes global warming.

gases combined with the speed, plus the passing through earths atmosphere. Or to answer in a word........friction!

Without its oxygen content the Earth's atmosphere would be composed almost entirely of nitrogen and would be chemically inert; oxygen causes the atmosphere to be chemically active (and breathable by humans).

The greenhouse effect causes the earth's atmosphere to hold in more heat radiation than it should. It is caused by envirormentally harmful chemicals entering the atmosphere, like carbon dioxcide. This ,in turn, causes the global temperature to increase global warming.

Because of friction with the atmosphere. A returning spacecraft is moving very fast and impact with air molecules causes the heating.

Gas does not directly cause Ice to melt. However if you are talking about glaciers then the gas Carbon Dioxide (CO2) causes the earths atmosphere to heat up (because it traps more of the Sun's heat) and this causes glaciers to melt - because the Earths climate is hotter.

No, it has changed over time. The original atmosphere of the Earth was mostly carbon dioxide with some water vapour, ammonia and methane, and was probably formed by volcanic outgassing. Living things introduced oxygen, and were one of the causes of reduced carbon dioxide. The ammonia then reacted with the oxygen.

The moons orbit causes the water to do this. The gravitational pull of the moon causes the water to be pushed and pulled

The heating of the air goes up while heating and when it gets to the top and goes to the bottom it cools

by creating carbon dioxide and monoxide(look in dictionary) which damages the o-zone layer which causes gobalwarming

Friction caused by the Earths atmosphere heats up the outer surface, making it glow.

The has molecules in the earths atmosphere. The speed of the meteor against these will cause a lot of friction, enough to burn it.

The Earths magnetic field is always shifting

The sun is one factor that causes the atmosphere to get hotter.

Air currents affect heat by absorbing the particles which causes the particles to expand to make it even hotter.

Shooting stars are actually asteroids that pass through the edge of our atmosphere.