1) Why bitcoin is falling so harshly?
Demand and supply forces , after a long rally Bitcoin usually takes a correction back to those rally.
2) Why altcoins fall when bitcoin is falling?
This is how the algorithm of the market works it is set that Bitcoin drives the entire Cryptos.
4) When will bitcoin go bull again and when is the resistance for current market?
Bull run usually kick start after every having , So Buy and HODL Bitcoin for 4 years
Resistance is at ATH