What are 3 challenges an organism would need to overcome to thrive in the deep sea

Organisms living in the deep ocean must be adapted to survive under extreme pressure, limited light, cold temperatures, and other factors. Organisms living in the deep ocean must survive in a physical environment that is radically different from ocean habitats near the sea surface.

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.