What is a stem? Describe the parts of the stem and its normal functions.

(N/A) $\rightarrow$ The stem is the ascending part of the plant axis that bears branches, leaves, flowers, and fruits. It develops from the $plumule$ of the embryo of a germinating seed.
$\rightarrow$ The stem is characterized by the presence of $nodes$ and $internodes$. The region of the stem where leaves are born is called a $node$, while $internodes$ are the portions between two nodes.
$\rightarrow$ The stem bears buds, which may be terminal or axillary. It is generally green when young and later often becomes woody and dark brown.
$\rightarrow$ Main functions of the stem:
$(i)$ Spreading out branches bearing leaves, flowers, and fruits.
$(ii)$ It conducts water, minerals, and photosynthates (food) between roots and leaves.
$(iii)$ Some stems perform specialized functions such as storage of food, mechanical support, protection, and vegetative propagation.