Why is throttle and clutch coordination especially important when starting a motorcycle from a stop on a steep uphill?

1. Too little throttle stalls the engine and too much spins the rear wheel; the clutch must release smoothly to use available traction
2. The clutch must be fully released before any throttle is applied
3. The throttle should be at idle and the bike pushed by passenger weight
4. The front brake must be applied while accelerating