Answers:-
To discourage bad people trying to tamper/change any confirmed transaction in any block as they must tamper/change all the blocks within the network because of the linkage. All will break if they tamper one.
Current hash
Previous hash
Tx list
Nonce
Target
It is Important for the blocks to be linked cryptographically together in order to maintain security. If a change happens in one block then all blocks in front of it will be changed as well.
The block structure of bitcoin looks like a chain of blocks that are linked together by a cryptographic puzzle and every four years the blocks halve in size.
1.To make sure non of the previous blocks have been manipulated after they have been added to the blockchain.
2. Hash of previous block, hash of current block transactions, nonce - all hashed together…
You mean the block reward? 
The reward is actually just a special kind of transaction called a coinbase 
It is important because if you change anything that has been recorded on the chain it changes everything upfront and makes it that there is no sense in term of incentive to remine the whole chain
Block structure:
hash of previous block
transactions proposed
nonce number
Based on these data hash is derived, then compared to target, and if below, then block is being added to the chain
It is important to keep the integrity of the chain and its transactions immutable. If a transaction is modified in a block, its hash (fingerprint) changes and then following block linked to it change too.
Looks like this:
Source: https://bitcointalk.org/index.php?topic=4312629.0
Each new block is created based on the transactions of the previous block.
Hashes of the previous and new blocks, transaction details, nonce.
1 This ensure the stability of the blockchain, as a change in any earlier block in the chain will produce a totally different chain which will be ignored (rejected) by the community.
2 Each block contains its own unique hash value, which is made up of the hash value from the previous block, the blocksize, transaction counter, transactions, current target and the nonce, which is a (variable) random number. The miners try different values for the nonce such that when all the attributes are hashed the hash value is lower than a specified target. the first miner to achieve this wins the prize of the mining fee plus transaction fees, and their block goes into the blockchain to become immortalised.
1). It is important so that they all in a sense secure each other because of their dependence and the natural game theory of mining.
2). A chain of blocks. Inside the block is the previous hash, the transaction list, and the nonce.
1.)
It is important because otherwise the blockchain would be vulnerable.
The block hash is a unique fingerprint and cannot be faked.
2.)
It is called a merkle tree structure.
1.Aversion number and cryptographic hash, miners need to spend electricity configure the target to get reward security , The transactions themselves are not stored in the header, but this root is unique to those transactions, and is required to reconstruct them.
A difficulty target, used in generating provable cryptographic work (proof of work) for that block.
2.block is composed of a header and a long list of transactions. Inputs outputs Transaction hx, previous trxs, nodes, crypto puzzle target miner needs land best guess
The importance of blocks being linked together is that if one block is changed or even one transaction within a block is changed it will effect all previous blocks since they are hashed based on the each block and its previous block. This is the power of blockchain to maintain immutability.
The block structure in bitcoin is based on this immutability since all blocks are linked to another block and if one transaction is changed then all the blocks will be effected.
By using the hash from the previous block, in the hash for the latest block and the puzzle to be solved using the previous block content and previous link, the time and effort required to make a change to a historic transaction anywhere in the blockchain makes in practically impossible to solve and regenerate all the links by the miners. It ensures the integrity of the data in the blockchain.
2.What does the block structure look like in bitcoin?
Hash of Previous Block
Transactions in this Block
Nonce (a random number)
The merkle tree only consists of txids and is part of the block, that is connected to a chain, which is more similar to a linked list
Response
It is important that the blocks are cryptographically linked because it ensures that the hash from the prior block is unique and linked to the subsequent block. So if any previous block is changed, the rest of the chain moving forward is invalid and must be re-mined. This helps to add security and also condenses information from prior blocks.
The block structure consists of:
a) block header
b) Nonce
c) Transactions (Tx list)
d) Previous block hash
e) Blocksize (size of Tx)
It’s important because it makes it extremely difficult to change/alter a transaction in a previous block because it will then change the hash value, which in turn breaks the chain.
The block structure includes the hash from the previous block, the transactions included in the current block, the nonce, as well as the current block hash.
1. Why is it important that the blocks are cryptographically linked together?
It is what makes the blockchain immutable (you can't go back and remove transactions already on it) as removing one transaction would invalidate not just that block but linked blocks. This immutability is part of the increased security of blockchain and its trustlessness.
2. What does the block structure look like in bitcoin?
It is a linked list data structure consisting of blocks linked together via hash pointers. The blocks themselves contain block headers (including amongst other things hash of the current block(merkle root), hash of the previous block, and the nonce) and hash pointers (which point to the location of the previous block and contain the hash of it, so you can verify if it has been changed).
