Strengthen the gene pool 

Nice Series, btw if you are new heres a tip: Using the rocks as a tool can be really helpful when you bash 2 of them together like granite or basalt, for example 2 basalt bashed into eachother make a basalt chopper and 2 granite make a granite grinder, you can use the grinder on stuff like horsetail leaves and khat leaves to enhance their healing effects meanwhile the basalt chopper speeds up altering and butchering by 2x which is very overpowered