Why does the clutch pedal have no resistance?

my uncle kept telling me that he was wanting to have me change his clutch on his 98 chevy s10 and when i went out there to see what it was doing i came to the conclusion that it was either the clutch hydraulic line or the clutch master cylinder. its lost all pressure. the engine will turn over in gear. we put it in neutral and staryted it and it wouldn't go into gear which is telling me that the clutch is not engaging. what is most likely the problem.
Why does the clutch pedal have no resistance?
It sounds like the clutch cable is broken. If it's a hydraulic clutch, check the clutch fluid level. If it's ok, then the master or slave cylinder needs changing. I've also seen one where the clutch fork was broken. This required dropping the transmission to repair.
Why does the clutch pedal have no resistance?
the clutch itself could be broken, if it is a hydrolic line then like you said there will be a problem with the pressure some wear, check everywear along the line for leaking oil, if there's no leak and the oil reservoir is full then it's probably the clutch it self?
The way a clutch is designed is that it is always engaged. Pressing the pedal disengages the clutch. Your problem is a pressure leak. Check to make sure the reservoir is full, if it is, bleed the line.