(a) Describe how a Merkle Tree is used to summarize a set of transactions included in a block. Illustrate your answer with a diagram showing how a Merkle tree is formed from a set of 4 transactions. (5 Marks) (b) In your own words, describe the concept of unspent transaction output (UTXO) of Bitcoin. Illustrate your answer with a diagram showing at least 5 transactions and with 2 UTXOs. Your diagram should include transaction amount and indicate transaction outputs belonging to the set of UTXOs