That's mean alternatively, if btc falls flat altcoin will dies off. What their deep relationship? Why btc important to altcoin, what's the connection in between? Will altcoins really survive without btc?
Actually Bitcoin is the first coin and btc has more than 40% dominance of the whole crypto market. whenever btc price drops , it means people are getting out of the crypto market which cause other altcoins dump. Altcoins will down more than btc because Altcoins buyers are mostly new users or big whale who are not long term holder while Most of btc holder are for long term.
Altcoins can survive without btc in one situation, when btc dominance down more than 15% then altcoins will almost free from btc and we will not see any big change in alt price with btc price change. Sometimes we seeing that some Altcoins pumped hard with btc dump like memecoins and fan coins.
I couldn't understand your English but I can tell you that alts have much more upside than BTC. BTC is obsolete and has no smart contract functionality. The best way to make money in crypto is to invest in new projects before they are listed on large exchanges and price trackers. Projects like 0xMR, SimpAI, Shardeum, Q Blockchain, zkSync...
New projects are risky and you don't know whether they will be listed in any big exchange or not. The project can fail at the initial stage so i will not recommend investing in any new project. Btc is best coin to invest in if you want secure investment while investing in big Altcoins are also right but new projects are not free from high risk