you can put a straight peace of wood and tie a string around and it will grow and be straight
A bit more:
If you're asking why a tree grows straight up, it's because trees, like all plants, grow towards light. And since the sun is up, the trees grow upwards, towards the light, resulting in the main trunk of the tree growing straight up.
Inertia
your spine....
some ppl have naturally straight hair...
the roots help the tree from falling down
keeps it swimming straight
Tree trunks are straight and branchless in their lower parts in their efforts to grow tall.
no there not warm blooded
You just buy a small tree from a nearby store. You water it everyday and give it some sunlight and it grows! You keep a tree straight by usually getting a metal stick or rod and tying it against the tree. It usually helps to keep it straight. :)
An evergreen tree, pine, christmas, you get the picture.
Some are, some are not.
our leg bones and leg muscles
left autrium