An example answer would be:
The second sentence is correct.
Which would be an answer to this question:
Which sentence is correct? “I is human” or “I am human”?
An answer like, "The second sentence is correct" is inappropriate for this site and should probably get deleted.
While a short answer like that does answer the literal question, for your answer to be helpful it must address the aspect of English that the asker doesn't know.
So in this case, the shortest possible valid answer would be something like this:
"I am human" is correct because the subject "I" takes the first person singular form of "to be", which is "am".
This answer shouldn't get deleted, but it still isn't great. It really should also mention the present simple, should say that "is" is the third person singular form, and maybe should include the full chart for simple present.
@gotube's answer is great, but there's another reason why such answers are often deleted, which is applicable to all sites in the network.
Suppose somebody else answers as follows:
The first sentence is correct.
How are we supposed to determine who is right? In this case, it's rather obvious, but there are definitely questions where the right answer depends on, let's say, whether it's about American or British English (and the question author didn't specify). Adding good arguments to support your answer makes it easier for the community to verify it's correct, and more likely to gain upvotes.