That's an interesting question, and there are many, many answers. Truthfully, we don't know for sure, because we haven't met any real aliens that we know of, but there are a lot of theories by authors and regular people. Here are some of them:
There are no aliens that we even know of. So, no.
Much better! Just watch that "e" at the end of "breathe." And we don't know yet. We have not yet made contact with alien life forms.
There is no such thing as aliens but if they did exist then they could never breath
The aliens dont actually breath, their not even alive, Its all to make money
if its breathing, and you know this by the steam on the lid of the pod. the breath steam is not wet, it is just vapour, but condensation can also form, which is wet and you need to get rid of it otherwise the water will drip onto your alien and the goo and both will die if it keeps happening.
if you see steam then it is alive but do not put it in your pocket because then it will not be able to breath so and if you do not see steam then it is dead so that is why
THE best alien of ben-10 ultimate alien is alien x.
Depends on which type of alien it is. ET alien? Super 8 Alien, Independence Day Alien?, or is it Alien 1-2-3 Series Alien?
Alien.
Alien , Aliens , Alien 3 and Alien Resurrection .
If he was evolved for that gravity, pressure, temperature and atmospheric composition, he'd be asking how can an alien live on Earth? After all, from a Jovian standpoint, we are far too hot a planet, the gravity is too small to hold a properly thick atmosphere, and we have "poisonous" levels of Oxygen all over!
There are 4 alien films: Alien, Aliens, Alien3, Alien resurrection