Not importing packages right

I've been trying to make a simple mod that increases the spawn rate of zombies on the overworld. I have tried importing the following 3 things:
 

import net.minecraft.world.biome.MobSpawnInfo;
import net.minecraft.world.entity.EntityClassification;
import net.minecraftforge.event.world.BiomeLoadingEvent;

However, these three packages appear to throw errors, giving a "cannot resolve symbol" error for the words "world", "EntityClassification", and "biome". Is there any way I can fix this?
I am using intelliJ to write the mod, with forge 1.20.6, with parchment mapping. I've double checked that all the versions line up and are the same, and the client game ran fine without the mod.