Its much like an std or when a cat fights another cat that is infected. Also when the cat is malnourished.
It depends on the cat. If it is young and needing a playmate it may like to have another playmate. However older cats would usually find it difficult to adjust to another cat, so would probably be happier as an only cat.
no another is something different like a cat is different from a dog
They don't like the taste. Carnivores have a different taste then omnivores.
They could be running away because they don't like the cat or the cat has already maybe hurt them once before.
I believe this is so because when another another cat enters the house the currently living-there cat is wondering Why do you bring another cat here? I am your cat! So I believe that the cat is jealous that another cat is in the house or you have recently touched another cat. Your cat has picked up the scent of that other cat. I know this because of experiences with my cat. Your cat is jealous that the other cat interacted with you.
The cat returns
You can, but you don't have to. If you already have a cat, base your decision on its personality. If it is very anti-social, don't get another cat. If your cat is friendly, you can get another cat. But if your friendly cat doesn't like the new cat, get rid of it. If your cat doesn't care, you could get one, but the decision is always up to you. I'm not a professional, but this is how I would approach it.
It sounds like your cat was in a nasty fight with another cat. Consider not letting your cat roam until it is fully healed.
Well you would like to know that because you want to know if the cat is going to get pregnant or get another cat pregnant....
Another name for a cat is a feline.
Get another cat...out them both outside...let them socialize...thats like asking how do you make toast with break and a toaster...