Is Blockchain a single linked list?

Question

Seen as datatype, is Blockchain a single linked list? As each block refers to the previous block using a hash.
Or is it some kind of tree?

Answer 1

The way a blockchain is represented as a singly linked list. Each block has a hash of the previous block which can be thought of as a pointer to previous block.

Some differences are that in a linked list, there are generally more operations for a linked list that are not available in a blockchain, most notably being able to remove a block and to add a block in the middle of the list/chain.

In the bitcoin blockchain, and probably others, each transaction in the block is stored in a Merkle Tree . The blockchain is not a tree.