Resistances in Biomutant prevent you from taking damage in hazardous areas of the game of the matching type of which there are 5: Heat, Cold, Radioactivity, Biohazard and Hypoxia.
If you’re exploring a Radioactive area, your Radioactivity Resistance will not only make it take longer for you to become affected, but will also reduce the damage you take once you are. The same is true for all other hazards, and Resistances.
During the Character Creation you will have a total of 25% Resistance (except for Hypoxia), and you can spend this in any way possible using a system nearly identical to Attributes. Don’t worry too much about this aspect, as you will gain more Resistances later on from your Gear.
All Biomutant Resistances
Heat Resistance
Resistance to hot environments, it extends the time it takes for you to reach 100% Heat.
Biohazard Resistance
Resistance to Biohazardous environments, it extends the time it takes for you to reach 100% Biohazard.
Cold Resistance
Resistance to Cold environments, it extends the time it takes for you to reach 100% Cold.
Radioactivity Resistance
Resistance to Radioactive environments, it extends the time it takes for you to reach 100% Radioactivity.