The block also contains a version that needs to be updated once the block changes, this would make old blocks invalid on the new nodes, making the fork irreversible. 
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Miners have their own nodes they connect to. Iām not sure why the answer is structured like this, but a block canāt be the same if it has different contents.
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which version ,I didnt understand you , can you please elaborate further more ?
thank you
so basically , i was correct , and the quiz was wrong ??
The block header also contains the block version:
https://en.bitcoin.it/wiki/Block_hashing_algorithm
No, because its not the same block.
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1)thank you , iāll check the link .
2)hmm , but the block clearly doesnt have the same contents when its solved by two differnet miners at the same time . so the quiz is also wrong , isnāt it? 
The correct answer is that Different miners find a block at the same height at the same time and is not the same, so the quiz is right. Its a bit of a trick question
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Hi Team,
If on the same block height there are two blocks, and these two are different, once one of the two parts in the blockchain is cancelled how is the information added from the previous cancelled blocks in the the remaining single blockchain? Meaning, do the block height gets re numbered? , because the two blocks on the same block height are differetā¦
Thank u hope quest is clear. Thnx
Hi Team,
What happens to the transactions kept from a stale block, do they get cancelled, or sent back to the mempool?
Thnx
Leo
There can only be 1 block on a certain blockheight, if 2 miners accidentally create a valid block on that blockheight, it depends on wich one the next miner will mine on top of it. If there are transactions that are not included in the surviving block, the transansactions in the loosing stale block go back to the mempool, so miners can still include them later on. Thatās why you better wait for more confirmations. The network will always agree on the longest blockchain with the most proof of work
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Just some confirmations here: Thanx Team
It sounds like in order for a node to update it must update on its own will, it doesnāt happen automatically, correct?
As long as thereās 1% of the total of nodes who donāt agree upon new update there will most surely be hard forks, correct?
Hi Filip! I was wondering, do miners get rewarded for the stale block (since they guessed the correct nouce and technically added a block to the chain)? How does it work? Thank you
Block reward is part of a special tx called a coinbase. If the block is dropped, so is the reward for that block.
So does this mean that the country or continent with the most miners will produce the most blocks ā¦and if so, how would that impact on decentralisation?
Where do invalid blocks go? Are they stored or deleted ?
Yes, atm china has by far the most mining power in the network and is not good for decentralization really. The only solution is to set more miners outside.
They donāt go anywhere. Some modified nodes might be able to store them, but what would be the point of doing that anyway?
Hi all, I have a question regarding hard forks.
Why would the miners/nodes not eventually accept only the longest chain (as per PoW) into the network (which should stem from the most updated version most of the time, as they accept more types of blocks)? Do the portion of miners that havenāt updated their rule set simply refuse to implement the new protocol rules?
Thanks in advance!
If there is more than 51% of hash power in the hardfrok they will have the longest chain and old nodes would reject that chain. In case of such an upgrade the block version also gets upgraded to distinguish the blocks.
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Thanks for the reply!
So the old nodes are effectively rejecting the rule that states the longest chain should always be accepted into the network? Or perhaps they view themselves as a separate network, so that their old chain is the longest (and for now only) chain?