system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why doesn’t grass grow to be as tall as something like a tree?

I know that when a lawn is left uncut the grass can grow plenty taller than what it’s typically kept at, and there’s plenty of “tall grass” in the wild, but why does it stop growing before getting to much bigger heights; like that of trees?
gpt
The grass most English speakers think of are growing horizontally, along the ground. The upwards parts are just leaves. They’re pretty long, but not the same biomass as a tree. And, as others have mentioned, bamboo.