Why Altcoins price depends on bitcoin value ? Its always going up and down when the bit coin price change.
because bitcoin is a reference of all altcoin prices and investments in ico. this is why bitcoin is instrumental in the development of crypto value. the simplest main example. bitcoin is always used as an investment, mining, trading.
Although not all altcoin prices depend only on the market price of bitcoin. there are some altcoins which could stand alone and have a direct exchange rate with fiat money but bitcoin prices have a great effect on the whole of crypto price. if bitcoin prices drop very deeply. almost all altcoins suffer the same impact on the market. as is the case today..