thanks. I've realized that fermi level is the probability of occupancy of energy states. initially i thought it was the probability of occupancy of electrons. that is why i could'nt understand the role of holes in the shift in position of fermi level.
and for that first question, i meant...
if fermi level is defined for 0K, then how does it vary in a semiconductor with temperature.
also, why will the formation of holes affect the position of fermi level(by introducing acceptors). have i misunderstood something? please clear my doubt.