A tree's leaves are also responsible for the twin functions of respiration ... leaf blade is composed of tissue layers, each having an important part to play in a functioning leaf.

Each aspect has a name and is used as part of the ... The bark is a tree's natural armor and protection from external threats. Bark also has several physical functions; one is ridding the tree ...

you could print off pictures of different plants and get them to label the parts - e.g. roots, stem/trunk, leaves, flowers etc. They could include a short description of the function each part ...