Looking at my ol' rulebook (Revised ed., copyright '82, printed in '83), Life Support was thus:
5 pts Character may breathe underwater
10 pts ....does not have to breathe, immune to inhaled gas
15 pts ...immune to gasses absorbed through the skin
20 pts ...survive in space or under high pressure
25 pts ...need not eat or excrete
30 pts ...survive under conditions of extreme heat, cold, radiation, pressure, etc., although he still takes damage from attacks of these natures due to shock.
Each category includes all those above it, cost no END to use.