system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do trees transfer water and nutrition to its leaves ?

How do hundred-meter trees transfer water and nutrition to its leaves, despite gravity ?
gpt
Do you know how a dry paper towel will absorb more water than a wet paper towel? Roots do something kinda similar to make water get in them all the time. They will control their substances to make what's called osmosis keep water going in.

Then, they have very thin channels that go up the tree. Have you ever noticed how water tends to go up ever so slightly when it touches a cup or glass? That's called capilarity. Trees have channels so thin that water simply goes up, up, up.

But there's a limit how high water can get this way. So there's a third way. When sunlight hits leaves, some of the water evaporates. When one drop of water evaporates on the top of the tree, it creates a bit of pressure that makes one drop of water go up the same channel to the top of the tree. Almost like a very weak vacuum cleaner.

Along with the water, also salts and other nutrients the roots absorbed go up, too.