system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do plants circulate water and nutrients throughout their system without a heart?

As far as I know, plants don't have any kind of moving parts that help move water and nutrients from their roots to their crowns. So how do they do it? How do plants work against gravity? 

It would make more sense to me if plants worked like fungi, spreading throughout the earth until they're ready to reproduce, but no, upright plants are the whole organism. Is that not, like, super weird? 

Plants are so weird. Like, "Hi, I'm a plant. I eat sunlight and communicate using mycorrhizal fungi. I have no muscles, but still break through concrete slabs. I have no heart, but still move water from my roots to my leaves."
gpt
Osmotic pressure and capillary action. Osmosis is the force that keeps pure solvents (i.e. water) from flowing through a semipermeable membrane (i.e. the cell wall). This keeps structures in the plant from drying out essentially. Capillary action is what causes water and nutrients to flow through a plant to the leaves and back down. Its pretty much physics.