Why is my cat so erratic?

Whenever my cat hears someone jump or walk she perk her ears up and gets very alert. Is there any grounds why she is like that? And if she is laying on me and i move a touch bit she does the same thing!
It's a completely natural response. Cats are hunters. They are listening for their "prey"
Is my cat pregnate?
My cat is the same. Might be some feral breed into them you never know. Feral cats seem to be especially skidish.
My cats be lost for 3 days...
Answers:    Possible answers:
1.She was abused at some time and she doesnt trust any sounds she hear.
2.You have a quiet home and so thats what she's used to and sounds/other general public scare her.
3.She's just got a shy nature. Some cats are genetically predisposed to be nervous. I have one close to that.
Hope this helps
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