Why are humans not an invasive species?

on island x the species needed to adapt because they were being subject to predators which didn't inhabit island y.  

gag reflex, poor dentition, gum retraction

have a good day

the sun creates it's own light, also gives light and life to bunch of stuff like plants,animals,humans etc.photosyntesis is the process of making food which needs sun,water,nutrients etc.