When the bark of a tree is removed in a circular fashion all around near its base, it gradually dries up or dies because –

When the bark of a tree is removed in a circular fashion all around near its base, it gradually dries up and dies decause

It is harmful to sleep under a tree at night because the tree releases :

Water reaches great heights in trees because of suction pull caused by

In the nighttime, it is advised not to sleep under trees because

Which one among the following is not a part of vascular bundle in plants?