According to definition and structure of the Merkle Tree, apparently, the number of transactions in a block that inserted in a Merkle Tree structure must be even (and not odd), is not it?
Please see the following figure which shows a Merkle Tree:
All the examples that I have seen, are like this one, meaning that apparently always number of transactions in a Merkle Tree are even (ex. in the example above there are four transactions). Is there an example in which number of transactions would be odd? And what happens if number of transaction are odd? (ex. how to insert 5 transactions in above example?)