system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do different strains of cannabis have different effects? Isn't it all still just THC?
gpt
You know how with some vegetables or fruits there are a bunch of different varieties, like with apples or tomatoes, that are all technically the same fruit but maybe have slightly different tastes, colors and shapes from each other?  Like how one type of apple tastes a lot more bitter than a different type, or how some tomatoes grow really huge and others only the size of cherries.  All of them are from the same family, but have slightly different genetics from one another.  That's pretty much how different strains of marijuana work as well.  Slightly different genetics produces a slightly different plant that may have slightly different perceived effects - like how some strains give you a head rush and a bit of energy, and others give you more of a body high and can make you feel really lethargic like you just want to sink into a couch.