Final answer:
The given syllogism is invalid because the conclusion does not necessarily follow from the premises.
Step-by-step explanation:
A syllogism is a deductive argument consisting of two premises and a conclusion. In this given syllogism, the premises are 'All humans are mortal' and 'I am mortal', and the conclusion is 'Therefore, I am human'. To determine whether this syllogism is valid or invalid, we can evaluate if the conclusion necessarily follows from the premises. In this case, the conclusion does not necessarily follow because there could be other mortal beings that are not human. Therefore, the syllogism is invalid.