i hv some question that make me confused 
1 - is after the creation of the genesis block we can say that the network now is safe and it will be safe ? because all the upcoming blocks will be rely on that block ?
2 - is the Block Hash just the sum of the Txs in the block decrypted with Hash Function Tech + the previous block hash ( is those things considered as Input that gives the Output ( block hash ) ) ? is this correct ?
3 - is every Tx inside the block has its own Hash ?
4 - if someone in the network that own 15% of the global HashRate want to modify a block in which way he can do it (manually or ...) ?
5 - if someone or some entity in the network that own 51% of the global HashRate want to modify a block in which way he can do it (manually or ...) ?
6 - is the calculation that the miners do is some sort of x + 15 = 2 so they need to calculate this to create a block the first one who find x = -13 gets a reward ? is this correct ?
7 - if a miner A create a block he gets a reward from the network ?
8 - if a miner B just validate Txs don't create any block what he should get as a reward ?
1 - is after the creation of the genesis block we can say that the network now is safe and it will be safe ? because all the upcoming blocks will be rely on that block ?
2 - is the Block Hash just the sum of the Txs in the block decrypted with Hash Function Tech + the previous block hash ( is those things considered as Input that gives the Output ( block hash ) ) ? is this correct ?
3 - is every Tx inside the block has its own Hash ?
4 - if someone in the network that own 15% of the global HashRate want to modify a block in which way he can do it (manually or ...) ?
5 - if someone or some entity in the network that own 51% of the global HashRate want to modify a block in which way he can do it (manually or ...) ?
6 - is the calculation that the miners do is some sort of x + 15 = 2 so they need to calculate this to create a block the first one who find x = -13 gets a reward ? is this correct ?
7 - if a miner A create a block he gets a reward from the network ?
8 - if a miner B just validate Txs don't create any block what he should get as a reward ?