Have you looked these up in the dictionary and, if so, can you tell us exactly what in the various definitions you found has made you confused about the meaning of each word?
Also, have you had a look at the rules of these forums? They ask us to give context for our questions and to give our own ideas on what might be the answer, or at least specific details about our doubts, so that those helping us do not simply do our homework (or just work) for us.
The first two words are the only ones I can see that have definitions which overlap, and it is a little tricky to describe the exact difference between them.
The WR dictionary defines "degraded" as lowered in value or unrestrained by convention or morality. Personally, I wouldn't tend to use "degraded" in the second sense, talking about a person, although I would use it to describe, for example, a natural landscape which has been cleared and become full of weeds. Perhaps that's just my personal take on the word.
"Debased" means corrupted, made impure or lowered in value. I'd usually apply it to a person, I think, although you can apply it to other things. (The WR dictionary gives some good examples.)
"Abject" I would always use to modify a noun, for example "abject poverty" is a very common use of this word. To me, it means "utter" or "extremely deep". It seems to me to have a meaning that is quite different from the others you've listed.
"Depraved" I'd definitely apply to either a person or an activity. The WR dictionary gives good definitions for this word, listing it as meaning marked by immorality, hopelessly bad and/or having the nature of vice.