can vs could (Can it get any worse? vs Could it get any worse?)

[Daemon99]

Hi,

Can someone please tell me the difference between the following two sentences and when each of them is used?

1) Can it get any worse?
2) Could it get any worse?

Also, should there be an exclamatory mark after the sentences?
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Non-native speaker of English
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I intend to live forever - so far, so good.

[Haihao]

Both are OK. Also, question mark would be better for the both.

[Molly]

1) Can it get any worse? = Is there a real chance of it getting worse
2) Could it get any worse? = Is there a remote chance of it getting worse