You should keep a very close eye on her - she may have internal trauma like cracked ribs or a pneumothorax. If she isn't recovering within the next 12 hours you should take her to a vet for a full examination.
You kitten is very sick and could die. You need to take him or her to a vet immediately. If you cannot afford the treatment, please ask the vet where you can get free help for your kitten. The vet or his staff are obliged to tell you.
I think you mean purring -_-. purrrrfectly natural, just means they are happy. If you are seriously concerned that your cat is breathing abnormally, call a veterinarian (you can find them in the phone book) in your area and ask them about it.
you spell it like this Stepped. If you wanted to use it in a sentence then you could use it like this: I stepped up on the ladder.
Kittens are very playful animals. If a kitten shakes when it is eating it could just be excited and enjoying the meal. If the kitten seems to be distressed, the food could be hard to chew, it could be choking the kitten, the kitten may not like the flavor, or the kitten may be having an allergic reaction to the food.
CO2 regulates the body breathing functions. The normal range is 23 to 32. A level of 31 is within the normal range. High levels of CO2 could indicate a breathing problem.
Immediately take the wounded kitten to the vet before any serious defects could happen. Don't waste any time, there could be problems with the kitten and it could need medical attention
No, it is not. The word "kitten" is a noun. It could be replaced by the pronoun it, or where the gender is known, by he, him, she, or her.
Something could be seriously wrong with the kitten. Take it to a vet immediately! Sick kittens, especially if very young, can go downhill very very quickly and need to be treated as soon as possible.
Killer is a cute name for a kitten. If the kitten is a male, you could name it King.
It could be infected some how or it got something in it's foot. Also it could have stepped in some substance that it should not have stepped in. You should see your vet about that.
No it could be harmful
Yes.